Nutrition as therapy
Role of nutrition in the prevention of disease |
Calcium and Vitamin D: Their Potential Roles in Colon and Breast Cancer Prevention
Influence of Drinking Green Tea on Breast Cancer Malignancy Among Japanese Patients
Legumes and Soybeans: Overview of their Nutritional Profiles and Health Effects
Fruit and Vegetable Intake in Relation to Risk of Ischemic Stroke
Cardiovascular and Renal Benefits of Dry Bean and Soybean Intake
Long-Term Intake of Dietary Fiber and Decreased Risk of Coronary Heart Disease Among Women
Whole-Grain Consumption and Risk of Coronary Heart Disease: Results from the Nurses' Health Study
Pecans Lower Low-Density Lipoprotein Cholesterol in People with Normal Lipid Levels
Frequent Nut Consumption and Risk of Coronary Heart Disease in Women: Prospective Cohort Study
Dietary Factors in Relation to Rheumatoid Arthritis: A Role for Olive Oil and Cooked Vegetables?
Diet
and Cancer
Prevention: the Fiber First Diet
Williams
GM, Williams CL, Weisburger JH.
Toxicol Sci. 1999 Dec;52(2 Suppl):72-86.
Diet
can play a major role in cancer prevention. The international differences in
cancer incidence are largely accounted for by lifestyle practices that include
nutrition, exercise, and alcohol and tobacco use. About 50% of cancer incidence
and 35% of cancer mortality in the U.S., represented by cancers of the breast,
prostate, pancreas, ovary, endometrium, and colon, are associated with Western
dietary habits. Cancer of the stomach, currently a major disease in the Far
East, relates to distinct, specific nutritional elements such as excessive salt
intake. For these cancers, information is available on possible initiating
genotoxic factors, promoting elements, and prophylactic agents. In general, the
typical diet in the United States contains low levels of the potent carcinogenic
agents, heterocyclic amines, formed during the cooking of meats. It provides
only about half the potent appropriate fiber intake and is high in calories.
About twice as many calories as would be desirable come from fat, certain kinds
of which enhance the development of cancers. Other foods with functional
properties, such as soy products and tea, can be beneficial. To achieve
reduction in risk of certain cancers, diet must be optimized, primarily to
reduce caloric intake and the fat component. The latter should be 20% or less of
total caloric intake and fiber should be increased to 25-35 g per day for
adults. One approach to achieving these goals is the Fiber First Diet, a diet
designed around adequate fiber intake from grains, especially cereals,
vegetables, legumes, and fruits, which thereby reduces both calorie and fat
intake. Such dietary improvements will not only reduce cancer and other chronic
disease risks, but will contribute to a healthy life to an advanced age. A
corollary benefit is a lower cost of medical care.
Calcium
and Vitamin D: Their Potential Roles in Colon and Breast Cancer Prevention
Garland
CF, Garland FC, Gorham ED.
Ann N Y Acad Sci.
1999;889:107-119.
The geographic distribution of colon cancer is similar to the historical geographic distribution of rickets. The highest death rates from colon cancer occur in areas that had high prevalence rates of rickets--regions with winter ultraviolet radiation deficiency, generally due to a combination of high or moderately high latitude, high-sulfur content air pollution (acid haze), higher than average stratospheric ozone thickness, and persistently thick winter cloud cover. The geographic distribution of colon cancer mortality rates reveals significantly low death rates at low latitudes in the United States and significantly high rates in the industrialized Northeast. The Northeast has a combination of latitude, climate, and air pollution that prevents any synthesis of vitamin D during a five-month vitamin D winter. Breast cancer death rates in white women also rise with distance from the equator and are highest in areas with long vitamin D winters. Colon cancer incidence rates also have been shown to be inversely proportional to intake of calcium. These findings, which are consistent with laboratory results, indicate that most cases of colon cancer may be prevented with regular intake of calcium in the range of 1,800 mg per day, in a dietary context that includes 800 IU per day (20 micrograms) of vitamin D3. (In women, an intake of approximately 1,000 mg of calcium per 1,000 kcal of energy with 800 IU of vitamin D would be sufficient.) In observational studies, the source of approximately 90% of the calcium intake was vitamin D-fortified milk. Vitamin D may also be obtained from fatty fish. In addition to reduction of incidence and mortality rates from colon cancer, epidemiological data suggest that intake of 800 IU/day of vitamin D may be associated with enhanced survival rates among breast cancer cases.
Fish
Consumption and Cancer Risk
Fernandez
E, Chatenoud L, La Vecchia C, Negri E, Franceschi S.
Am J Clin Nutr.
1999 Jul;70(1):85-90.
Background:
Although several studies have investigated the relation between fish consumption
and the risk of cardiovascular diseases, less attention has been paid to the
relation between fish consumption and cancer risk.
Objective: The
relation between frequency of consumption of fish and risk of selected neoplasms
was analyzed by using data from an integrated series of case-control studies
conducted in northern Italy between 1983 and 1996.
Design: The overall
data set included the following incident, histologically confirmed neoplasms:
oral cavity and pharynx (n = 181), esophagus (n = 316), stomach (n = 745), colon
(n = 828), rectum (n = 498), liver (n = 428), gallbladder (n = 60), pancreas (n
= 362), larynx (n = 242), breast (n = 3412), endometrium (n = 750), ovary (n =
971), prostate (n = 127), bladder (n = 431), kidney (n = 190), thyroid (n =
208), Hodgkin disease (n = 80), non-Hodgkin lymphomas (n = 200), and multiple
myelomas (n = 120). Control subjects were 7990 patients admitted for acute,
nonneoplastic conditions unrelated to long-term modifications of diet. Odds
ratios (ORs) were computed for subsequent levels of fish consumption compared
with no or occasional consumption (<1 serving/wk) by using multiple logistic
regression, including terms for several covariates.
Results: There was a
consistent pattern of protection against the risk of digestive tract cancers
with fish consumption: oral cavity and pharynx, OR = 0.5 for the highest
compared with the lowest level of consumption; esophagus, OR = 0.6; stomach, OR
= 0.7; colon, OR = 0.6; rectum, OR = 0.5; and pancreas, OR = 0.7. There were
inverse trends in risk of larynx (OR = 0.7), endometrial (OR = 0.8), and ovarian
(OR = 0.7) cancers and multiple myeloma (OR = 0.5). No pattern of cancer risk in
relation to fish consumption was observed for cancers of the liver, gallbladder,
breast, bladder, kidney, or thyroid or for lymphomas.
Conclusion: This
study suggests that the consumption of even relatively small amounts of fish is
a favorable indicator of the risk of several cancers, especially of the
digestive tract.
Folate
and Cancer Prevention: A New Medical Application of Folate Beyond
Hyperhomocysteinemia and Neural Tube Defects
Kim
YI.
Nutr Rev. 1999 Oct;57(10):314-321.
Folate
is an important cofactor in the transfer of one-carbon moieties and plays a key
role in DNA synthesis, repair, and methylation. The role of folate has greatly
evolved from the prevention of macrocytic anemia to the prevention of
cardiovascular disease and neural tube defects. More recently, epidemiologic,
animal, and clinical evidence suggests that folate may also play a role in
cancer prevention. Two recently published large, prospective epidemiologic
studies suggest that maintaining adequate levels of serum folate or moderately
increasing folate intakes from dietary sources and vitamin supplements can
significantly reduce the risk of pancreatic and breast cancer, respectively.
This protective effect of folate appears to be operative in subjects at risk for
developing these cancers, namely, male smokers for pancreatic cancer and women
regularly consuming a moderate amount of alcohol for breast cancer. Because the
expanding role of folate nutrition in cancer prevention has major public health
implications, research is required to clearly elucidate the effect of folate on
carcinogenesis.
Vegan
Proteins May Reduce Risk of Cancer, Obesity, and Cardiovascular Disease by
Promoting Increased Glucagon Activity
McCarty
MF.
Med Hypotheses.
1999 Dec;53(6):459-485.
Amino
acids modulate the secretion of both insulin and glucagon; the composition of
dietary protein therefore has the potential to influence the balance of glucagon
and insulin activity. Soy protein, as well as many other vegan proteins, are
higher in non-essential amino acids than most animal-derived food proteins, and
as a result should preferentially favor glucagon production. Acting on
hepatocytes, glucagon promotes (and insulin inhibits) cAMP-dependent mechanisms
that down-regulate lipogenic enzymes and cholesterol synthesis, while
up-regulating hepatic LDL receptors and production of the IGF-I antagonist
IGFBP-1. The insulin-sensitizing properties of many vegan diets--high in fiber,
low in saturated fat--should amplify these effects by down-regulating insulin
secretion. Additionally, the relatively low essential amino acid content of some
vegan diets may decrease hepatic IGF-I synthesis. Thus, diets featuring vegan
proteins can be expected to lower elevated serum lipid levels, promote weight
loss, and decrease circulating IGF-I activity. The latter effect should impede
cancer induction (as is seen in animal studies with soy protein), lessen
neutrophil-mediated inflammatory damage, and slow growth and maturation in
children. In fact, vegans tend to have low serum lipids, lean physiques, shorter
stature, later puberty, and decreased risk for certain prominent 'Western'
cancers; a vegan diet has documented clinical efficacy in rheumatoid arthritis.
Low-fat vegan diets may be especially protective in regard to cancers linked to
insulin resistance--namely, breast and colon cancer--as well as prostate cancer;
conversely, the high IGF-I activity associated with heavy ingestion of animal
products may be largely responsible for the epidemic of 'Western' cancers in
wealthy societies. Increased phytochemical intake is also likely to contribute
to the reduction of cancer risk in vegans. Regression of coronary stenoses has
been documented during low-fat vegan diets coupled with exercise training; such
regimens also tend to markedly improve diabetic control and lower elevated blood
pressure. Risk of many other degenerative disorders may be decreased in vegans,
although reduced growth factor activity may be responsible for an increased risk
of hemorrhagic stroke. By altering the glucagon/insulin balance, it is
conceivable that supplemental intakes of key non-essential amino acids could
enable omnivores to enjoy some of the health advantages of a vegan diet. An
unnecessarily high intake of essential amino acids--either in the absolute sense
or relative to total dietary protein--may prove to be as grave a risk factor for
'Western' degenerative diseases as is excessive fat intake.
Influence
of Drinking Green Tea on Breast Cancer Malignancy Among Japanese Patients
Nakachi
K, Suemasu K, Suga K, Takeo T, Imai K
Jpn J Cancer Res.
1998 Mar;89(3):254-261.
Inhibitory
effects of green tea on carcinogenesis have been investigated in numerous
laboratory studies using (-)-epigallocatechin gallate (EGCG) or crude green tea
extract, and there is also some epidemiologic evidence. Further, EGCG has been
reported to inhibit the growth of cancer cells, lung metastasis in an animal
model, and urokinase activity. In this study, we first examined the association
between consumption of green tea prior to clinical cancer onset and various
clinical parameters assessed at surgery among 472 patients with stage I, II, and
III breast cancer. We found that increased consumption of green tea was closely
associated with decreased numbers of axillary lymph node metastases among
premenopausal patients with stage I and II breast cancer and with increased
expression of progesterone receptor (PgR) and estrogen receptor (ER) among
postmenopausal ones. Since these are potential prognostic factors, we then
investigated the prognosis of breast cancer with special reference to
consumption of green tea, in a follow-up study of these patients. We found that
increased consumption of green tea was correlated with decreased recurrence of
stage I and II breast cancer (P < 0.05 for crude disease-free survival); the
recurrence rate was 16.7 or 24.3% among those consuming > or = 5 cups or <
or = 4 cups per day, respectively, in a seven-year follow-up of stage I and II
breast cancer, and the relative risk of recurrence was 0.564 (95% confidence
interval, 0.350-0.911) after adjustment for other lifestyle factors. However, no
improvement in prognosis was observed in stage III breast cancer. Our results
indicate that increased consumption of green tea prior to clinical cancer onset
is significantly associated with improved prognosis of stage I and II breast
cancer, and this association may be related to a modifying effect of green tea
on the clinical characteristics of the cancer.
Legumes
and Soybeans: Overview of their Nutritional Profiles and Health Effects
Messina
MJ.
Am J Clin Nutr.
1999 Sep;70(3 Suppl):439S-450S.
Legumes
play an important role in the traditional diets of many regions throughout the
world. In contrast in Western countries beans tend to play only a minor dietary
role despite the fact that they are low in fat and are excellent sources of
protein, dietary fiber, and a variety of micronutrients and phytochemicals.
Soybeans are unique among the legumes because they are a concentrated source of
isoflavones. Isoflavones have weak estrogenic properties and the isoflavone
genistein influences signal transduction. Soyfoods and isoflavones have received
considerable attention for their potential role in preventing and treating
cancer and osteoporosis. The low breast cancer mortality rates in Asian
countries and the putative antiestrogenic effects of isoflavones have fueled
speculation that soyfood intake reduces breast cancer risk. The available
epidemiologic data are limited and only weakly supportive of this hypothesis,
however, particularly for postmenopausal breast cancer. The data suggesting that
soy or isoflavones may reduce the risk of prostate cancer are more encouraging.
The weak estrogenic effects of isoflavones and the similarity in chemical
structure between soybean isoflavones and the synthetic isoflavone ipriflavone,
which was shown to increase bone mineral density in postmenopausal women,
suggest that soy or isoflavones may reduce the risk of osteoporosis. Rodent
studies tend to support this hypothesis, as do the limited preliminary data from
humans. Given the nutrient profile and phytochemical contribution of beans,
nutritionists should make a concerted effort to encourage the public to consume
more beans in general and more soyfoods in particular.
Diet
High in Whole and Unrefined Foods Favorably Alters Lipids, Antioxidant
Defenses, and Colon Function
Bruce
B, Spiller GA, Klevay LM, Gallagher SK.
J Am Coll Nutr.
2000 Feb;19(1):61-67.
Objective:
Diets rich in whole and unrefined foods, like whole grains, dark green and
yellow/orange-fleshed vegetables and fruits, legumes, nuts and seeds, contain
high concentrations of antioxidant phenolics, fibers and numerous other
phytochemicals that may be protective against chronic diseases. This study
compared the effects of a phytochemical-rich diet versus a refined-food diet on
lipoproteins, antioxidant defenses and colon function.
Methods: Twelve
hyperlipidemic women followed two diets for four weeks starting with a
refined-food diet. Subjects then directly crossed over to the phytochemical-rich
diet. Duplicate, fasting serum lipids and single, fasting antioxidant enzymes
were measured at the end of the four-week refined-food diet period (baseline)
and again at the end of the phytochemical-rich diet period.
Results: Total
energy and total fat intake were similar during both diet periods, but there was
a decrease in saturated fat (SFA) of 61% in the phytochemical-rich diet group.
Dietary fiber, vitamin E, vitamin C and carotene intakes were 160%, 145%, 160%
and 500% more, respectively, than during the refined-food diet period. The
phytochemical-rich diet induced a drop of 13% in total cholesterol (TC) (p <
0.05) and 16% (p < 0.001) in low density lipoprotein-cholesterol (LDL-C).
Erythrocyte superoxide dismutase decreased 69% (p < 0.01) and glutathione
peroxidase dropped 35% (p < 0.01). Colon function was improved on the
phytochemical-rich diet.
Conclusions: A diet
abundant in phytochemically-rich foods beneficially affected lipoproteins,
decreased need for oxidative defense mechanisms and improved colon function.
MacGregor
GA.
Nutr Metab Cardiovasc Dis.
1999 Aug;9(4 Suppl):6-15.
Nutrition
plays a very important role in regulating blood pressure. If we reverted to our
evolutionary diet the problem of high blood pressure would disappear. However,
this is unlikely and we, therefore, need to identify the most important factors
in our diet that predispose to high blood pressure and, therefore, to vascular
disease. Studies clearly demonstrate the very important role of our current
intake of salt in our diet as being the major factor in regulating blood
pressure in populations. Other dietary factors have also been identified as
playing an important role, particularly potassium intake and fruit and vegetable
consumption. A more healthy diet,that is a diet with much less salt and
increased potassium through an increase in fruit and vegetable consumption, a
reduction in fat intake with substitution of saturated by monounsaturated fat, a
reduction in meat and dairy products with an increase in fish consumption will
have large effects on blood pressure but, at the same time, will decrease other
cardiovascular risk factors, particularly cholesterol and glucose intolerance.
This healthier diet will reduce cardiovascular disease and is similar to the
diet now being advocated for the prevention of some forms of cancer. Diet is by
far the most important environmental factor determining our longevity and for
those who wish to live longer, a change in diet as early in life as possible
will have substantial effects.
Fruit
and Vegetable Intake in Relation to Risk of Ischemic Stroke
Joshipura
KJ, Ascherio A, Manson JE, et al.
JAMA. 1999 Oct 6;282(13):1233-1239.
Context:
Few studies have evaluated the relationship between fruit and vegetable intake
and cardiovascular disease.
Objective: To
examine the associations between fruit and vegetable intake and ischemic stroke.
Design, Setting, and Subjects:
Prospective cohort studies, including 75 596 women aged 34 to 59 years in the
Nurses' Health Study with 14 years of follow-up (1980-1994), and 38683 men aged
40 to 75 years in the Health Professionals' Follow-up Study with 8 years of
follow-up (1986-1994). All individuals were free of cardiovascular disease,
cancer, and diabetes at baseline.
Main Outcome Measure:
Incidence of ischemic stroke by quintile of fruit and vegetable intake.
Results: A total of
366 women and 204 men had an ischemic stroke. After controlling for standard
cardiovascular risk factors, persons in the highest quintile of fruit and
vegetable intake (median of 5.1 servings per day among men and 5.8 servings per
day among women) had a relative risk (RR) of 0.69 (95% confidence interval [CI],
0.52-0.92) compared with those in the lowest quintile. An increment of 1 serving
per day of fruits or vegetables was associated with a 6% lower risk of ischemic
stroke (RR, 0.94; 95 % CI, 0.90-0.99; P =.01, test for trend). Cruciferous
vegetables (RR, 0.68 for an increment of 1 serving per day; 95% CI, 0.49-0.94),
green leafy vegetables (RR, 0.79; 95% CI, 0.62-0.99), citrus fruit including
juice (RR, 0.81; 95% CI, 0.68-0.96), and citrus fruit juice (RR, 0.75; 95% CI,
0.61-0.93) contributed most to the apparent protective effect of total fruits
and vegetables. Legumes or potatoes were not associated with lower ischemic
stroke risk. The multivariate pooled RR for total stroke was 0.96 (95% CI,
0.93-1.00) for each increment of 2 servings per day.
Conclusions: These
data support a protective relationship between consumption of fruit and
vegetables-particularly cruciferous and green leafy vegetables and citrus fruit
and juice-and ischemic stroke risk.
Cardiovascular
and Renal Benefits of Dry Bean and Soybean Intake
Anderson
JW, Smith BM, Washnock CS.
Am J Clin Nutr.
1999 Sep;70(3 Suppl):464S-474S.
Dry
beans and soybeans are nutrient-dense, fiber-rich, and are high-quality sources
of protein. Protective and therapeutic effects of both dry bean and soybean
intake have been documented. Studies show that dry bean intake has the potential
to decrease serum cholesterol concentrations, improve many aspects of the
diabetic state, and provide metabolic benefits that aid in weight control.
Soybeans are a unique source of the isoflavones genistein and diadzein, which
have numerous biological functions. Soybeans and soyfoods potentially have
multifaceted health-promoting effects, including cholesterol reduction, improved
vascular health, preserved bone mineral density, and reduction of menopausal
symptoms. Soy appears to have salutary effects on renal function, although these
effects are not well understood. Whereas populations consuming high intakes of
soy have lower prevalences of certain cancers, definitive experimental data are
insufficient to clarify a protective role of soy. The availability of legume
products and resources is increasing, incorporating dry beans and soyfoods into
the diet can be practical and enjoyable. With the shift toward a more
plant-based diet, dry beans and soy will be potent tools in the treatment and
prevention of chronic disease.
Long-Term
Intake of Dietary Fiber and Decreased Risk of Coronary Heart Disease Among
Women
Wolk
A, Manson JE, Stampfer MJ, et al.
JAMA. 1999 Jun 2;281(21):1998-2004.
Context:
Epidemiological studies of men suggest that dietary fiber intake protects
against coronary heart disease (CHD), but data on this association in women are
sparse.
Objective: To
examine the association between long-term intake of total dietary fiber as well
as fiber from different sources and risk of CHD in women.
Design and Setting:
The Nurses' Health Study, a large, prospective cohort study of US women followed
up for 10 years from 1984. Dietary data were collected in 1984, 1986, and 1990,
using a validated semiquantitative food frequency questionnaire.
Participants: A
total of 68782 women aged 37 to 64 years without previously diagnosed angina,
myocardial infarction (MI), stroke, cancer, hypercholesterolemia, or diabetes at
baseline.
Main Outcome Measure:
Incidence of acute MI or death due to CHD by amount of fiber intake.
Results: Response
rate averaged 80% to 90% during the 10-year follow-up. We documented 591 major
CHD events (429 nonfatal MIs and 162 CHD deaths). The age-adjusted relative risk
(RR) for major CHD events was 0.53 (95% confidence interval [CI], 0.40-0.69) for
women in the highest quintile of total dietary fiber intake (median, 22.9 g/d)
compared with women in the lowest quintile (median, 11.5 g/d). After controlling
for age, cardiovascular risk factors, dietary factors, and multivitamin
supplement use, the RR was 0.77 (95% CI, 0.57-1.04). For a 10-g/d increase in
total fiber intake (the difference between the lowest and highest quintiles),
the multivariate RR of total CHD events was 0.81 (95% CI, 0.66-0.99). Among
different sources of dietary fiber (eg, cereal, vegetables, fruit), only cereal
fiber was strongly associated with a reduced risk of CHD (multivariate RR, 0.63;
95% CI, 0.49-0.81 for each 5-g/d increase in cereal fiber).
Conclusions: Our
findings in women support the hypothesis that higher fiber intake, particularly
from cereal sources, reduces the risk of CHD.
Whole-Grain
Consumption and Risk of Coronary Heart Disease: Results from the Nurses'
Health Study
Liu
S, Stampfer MJ, Hu FB, et al.
Am J Clin Nutr.
1999 Sep;70(3):412-419.
Background:
Although current
dietary guidelines for Americans recommend increased intake of grain products to
prevent coronary heart disease (CHD), epidemiologic data relating whole-grain
intake to the risk of CHD are sparse.
Objective: Our
objective was to evaluate whether high whole-grain intake reduces risk of CHD in
women.
Design: In 1984,
75521 women aged 38-63 y with no previous history of cardiovascular disease or
diabetes completed a detailed, semiquantitative food-frequency questionnaire (SFFQ)
and were followed for 10 y, completing SFFQs in 1986 and 1990. We used pooled
logistic regression with 2-y intervals to model the incidence of CHD in relation
to the cumulative average diet from all 3 cycles of SFFQs.
Results: During
729472 person-years of follow-up, we documented 761 cases of CHD (208 of fatal
CHD and 553 of nonfatal myocardial infarction). After adjustment for age and
smoking, increased whole-grain intake was associated with decreased risk of CHD.
For increasing quintiles of intake, the corresponding relative risks (RRs) were
1.0 (reference), 0.86, 0.82, 0.72, and 0.67 (95% CI comparing 2 extreme
quintiles: 0.54, 0.84; P for trend < 0.001). After additional adjustment for
body mass index, postmenopausal hormone use, alcohol intake, multivitamin use,
vitamin E supplement use, aspirin use, physical activity, and types of fat
intake, these RRs were 1.0, 0.92, 0.93, 0.83, and 0.75 (95% CI: 0.59, 0.95; P
for trend = 0.01). The inverse relation between whole-grain intake and CHD risk
was even stronger in the subgroup of never smokers (RR = 0. 49 for extreme
quintiles; 95% CI: 0.30, 0.79; P for trend = 0.003). The lower risk associated
with higher whole-grain intake was not fully explained by its contribution to
intakes of dietary fiber, folate, vitamin B-6, and vitamin E.
Conclusions:
Increased intake of whole grains may protect against CHD.
Pecans
Lower Low-Density Lipoprotein Cholesterol in People with Normal Lipid Levels
Morgan
WA, Clayshulte BJ.
J Am Diet Assoc.
2000 Mar;100(3):312-318.
Objective:
To compare serum lipid profiles and dietary intakes of people with normal lipid
levels who consumed pecans and those who did not consume nuts.
Design: Eight-week,
randomized, controlled study of pecan treatment group vs control group. SUBJECT:
Nineteen people with normal lipid levels completed the study; 10 had been
randomly assigned to the pecan treatment group (7 women, 3 men, mean age = 45
+/- 10 years) and 9 to the control group (8 women, 1 man, mean age = 37 +/- 12
years).
Intervention: The
pecan treatment group consumed 68 g pecans per day for 8 weeks plus
self-selected diets. The pecans contributed 459 kcal and 44 g fat daily. The
control group avoided nuts and consumed self-selected diets.
Main Outcome Measures:
Total serum cholesterol, low-density lipoprotein cholesterol (LDL-C),
high-density lipoprotein cholesterol (HDL-C), and total triglyceride levels were
measured at the time of entrance to the study (baseline), week 4, and week 8.
Computer analyses were done on five 3-day food records.
Statistical Analysis:
Comparisons were made using analysis of variance or paired t test.
Results: LDL-C was
lowered in the pecan treatment group from 2.61 +/- 0.49 mmol/L at baseline to
2.35 +/- 0.49 at week 4 (P < .05) and to 2.46 +/- 0.59 at week 8 (P <
.05). At week 8, total cholesterol and HDL-C in the pecan treatment group were
significantly lower (P < .05) than in the control group (total cholesterol:
4.22 +/- 0.83 vs 5.02 +/- 0.54 mmol/L; HDL-C: 1.37 +/- 0.23 vs 1.47 +/- 0.34
mmol/L). Dietary fat, monounsaturated fat, polyunsaturated fat, insoluble fiber,
magnesium, and energy were significantly higher in the pecan treatment group
than in the control group. Body mass indexes and body weights were unchanged in
both groups.
Applications: Pecans
can be included in a healthful diet when energy intake and potential weight gain
are addressed.
Nut
Consumption, Vegetarian Diets, Ischemic Heart Disease Risk, and All-Cause
Mortality: Evidence from Epidemiologic Studies
Sabate
J.
Am J Clin Nutr.
1999 Sep;70(3 Suppl):500S-503S.
Perhaps
one of the most unexpected and novel findings in nutritional epidemiology in the
past 5 y has been that nut consumption seems to protect against ischemic heart
disease (IHD). Frequency and quantity of nut consumption have been documented to
be higher in vegetarian than in nonvegetarian populations. Nuts also constitute
an important part of other plant-based diets, such as Mediterranean and Asian
diets. In a large, prospective epidemiologic study of Seventh-day Adventists in
California, we found that frequency of nut consumption had a substantial and
highly significant inverse association with risk of myocardial infarction and
death from IHD. The Iowa Women's Health Study also documented an association
between nut consumption and decreased risk of IHD. The protective effect of nuts
on IHD has been found in men and women and in the elderly. Importantly, nuts
have similar associations in both vegetarians and nonvegetarians. The protective
effect of nut consumption on IHD is not offset by increased mortality from other
causes. Moreover, frequency of nut consumption has been found to be inversely
related to all-cause mortality in several population groups such as whites,
blacks, and the elderly. Thus, nut consumption may not only offer protection
against IHD, but also increase longevity.
Frequent
Nut Consumption and Risk of Coronary Heart Disease in Women: Prospective
Cohort Study
Hu
FB, Stampfer MJ, Manson JE, et al.
J Nutr.1999 Jun;129(6):1135-1139.
Objective:
To examine the relation between nut consumption and risk of coronary heart
disease in a cohort of women from the Nurses' Health Study.
Design: Prospective
cohort study.
Setting: Nurses'
Health Study.
Subjects: 86 016
women from 34 to 59 years of age without previously diagnosed coronary heart
disease, stroke, or cancer at baseline in 1980.
Main Outcome Measures:
Major coronary heart disease including non-fatal myocardial infarction and fatal
coronary heart disease.
Results: 1255 major
coronary disease events (861 cases of non-fatal myocardial infarction and 394
cases of fatal coronary heart disease) occurred during 14 years of follow up.
After adjusting for age, smoking, and other known risk factors for coronary
heart disease, women who ate more than five units of nuts (one unit equivalent
to 1 oz of nuts) a week (frequent consumption) had a significantly lower risk of
total coronary heart disease (relative risk 0.65, 95% confidence interval 0.47
to 0.89, P for trend=0.0009) than women who never ate nuts or who ate less than
one unit a month (rare consumption). The magnitude of risk reduction was similar
for both fatal coronary heart disease (0.61, 0.35 to 1.05, P for trend=0.007)
and non-fatal myocardial infarction (0.68, 0.47 to 1.00, P for trend=0.04).
Further adjustment for intakes of dietary fats, fibre, vegetables, and fruits
did not alter these results. The inverse association persisted in subgroups
stratified by levels of smoking, use of alcohol, use of multivitamin and vitamin
E supplements, body mass index, exercise, and intake of vegetables or fruits.
Conclusions:
Frequent nut consumption was associated with a reduced risk of both fatal
coronary heart disease and non-fatal myocardial infarction. These data, and
those from other epidemiological and clinical studies, support a role for nuts
in reducing the risk of coronary heart disease.
Are
Olive Oil Diets Antithrombotic? Diets Enriched with Olive, Rapeseed, or
Sunflower Oil Affect Postprandial Factor VII Differently
Larsen
LF, Jespersen J, Marckmann P.
Am J Clin Nutr.
1999 Dec;70(6):976-982.
Background:
The incidence of ischemic heart disease (IHD) in Crete was lower than expected
on the basis of blood lipid concentrations of participants in the Seven
Countries Study. A favorable effect of a high intake of olive oil on
thrombogenesis may have contributed to this finding.
Objective: We
compared the effects of virgin olive oil with those of rapeseed and sunflower
oils on blood coagulation factor VII (FVII), a key factor in thrombogenesis.
Design: In a
randomized and strictly controlled crossover study, 18 healthy young men
consumed diets enriched with 5 g/MJ (19% of total energy) olive oil, sunflower
oil, or rapeseed oil for periods of 3 wk. On the final day of each period,
participants consumed standardized high-fat meals (42% of energy as fat).
Fasting and nonfasting blood samples were collected after each period.
Results: Mean (+/-SEM)
nonfasting peak concentrations of activated FVII (FVIIa) were 11.3 +/- 5.1 U/L
lower after olive oil than after sunflower oil, an 18% reduction (P < 0.05).
Olive oil also tended to cause lower FVIIa peak concentrations than did rapeseed
oil (mean difference: 8.6 U/L, a 15% reduction; P = 0.09). There were no
significant differences between diets with respect to nonfasting factor VII
coagulant activity (FVII:c), prothrombin fragment 1+2 (F1+2), and tissue factor
pathway inhibitor (TFPI) concentrations, or with respect to fasting plasma
values of FVII protein, FVII:c, FVIIa, F1+2, or TFPI.
Conclusion: A
background diet rich in olive oil may attenuate the acute procoagulant effects
of fatty meals, which might contribute to the low incidence of IHD in
Mediterranean areas.
"The
SU.VI.MAX Study": A Primary Prevention Trial Using Nutritional Doses of
Antioxidant Vitamins and Minerals in Cardiovascular Diseases and Cancers.
SUpplementation en VItamines et Mineraux AntioXydants
Hercberg
S, Preziosi P, Galan P, et al.
Food Chem Toxicol.
1999 Sep-Oct;37(9-10):925-930.
The
"SUpplementation en VItamines et Mineraux AntioXydants" (SU.VI.MAX)
Study is a randomized double-blind, placebo-controlled, primary-prevention trial
which started in 1994 in France. This epidemiologic study is designed to test
the efficacy of a daily supplementation with antioxidant vitamins (vitamin C,
120 mg, vitamin E, 30 mg, and beta-carotene, 6 mg) and minerals (selenium, 100
microg, and zinc, 20 mg) at nutritional doses, in reducing the main causes of
premature death (cancers and cardiovascular diseases); 12,735 eligible subjects
(women aged 35 to 60 years, and men aged 45 to 60 years) were included in 1994
and will be followed up for 8 years. Participants undergo a yearly visit
consisting, every other year, of either biological sampling or clinical
examination. They also regularly provide information on health events and
dietary intake by filling out computerized questionnaires using the Minitel
Telematic Network. After 2 years of supplementation, biochemical indicators of
vitamin and trace element status reach reasonable level without reaching
concentrations as high as those observed in intervention studies, which tested
relatively high doses of antioxidants, and ended up with higher risk of
pathology.
Nutritional
Strategies in Cardiovascular Disease Control: An Update on Vitamins and
Conditionally Essential Nutrients
Kendler
BS.
Prog Cardiovasc Nurs.
1999 Autumn;14(4):124-129.
Several
nutritional interventions for cardiovascular disease (CVD) prevention and
therapy have recently appeared in the biomedical literature. These include
appropriate use of several vitamins (E, C, B6, folate) and conditionally
essential nutrients (CoQ10, L-arginine, propionyl L-carnitine). Possible
undesirable consequences of long term nutritional supplementation with vitamin E
and of adverse drug-nutrient interactions between the statins and CoQ10 are also
considered. Although additional intervention studies are needed, current
scientific evidence generally supports nutritional supplementation with these
nutrients as an effective adjunctive strategy for CVD control.
Serum
Vitamins, Carotenoids, and Angina Pectoris: Findings from The National
Health and Nutrition Examination Survey III
Ford
ES, Giles WH.
Ann Epidemiol. 2000 Feb;10(2):106-116.
Purpose:
Whether various vitamins and carotenoids can protect against ischemic heart
disease remains an unsettled question.
Methods: We
performed a cross-sectional analysis of data from National Health and Nutrition
Examination Survey III (1988-1994) and examined the associations between serum
vitamins A, C, E, and B12, serum folate, red blood cell folate, serum
carotenoids, and angina pectoris in a representative population-based sample of
11,327 men and women aged 35->90 years.
Results: After
adjusting for age, sex, race or ethnicity, education, smoking status, systolic
blood pressure, serum cholesterol, high-density lipoprotein cholesterol, history
of diabetes mellitus, body mass index, and physical activity with multiple
logistic regression analysis, no significant associations were present for any
of the serum vitamin concentrations and angina pectoris. Significant linear
trends were observed for serum concentrations of alpha-carotene (p < 0.001),
beta-carotene (p = 0.026), and beta-cryptoxanthin (p = 0.003). Compared with
participants with carotenoid concentrations in the lowest quartile, participants
with concentrations in the highest quartile had odds ratios for angina pectoris
of 0.45 (95% confidence interval (CI) 0.31-0.65), 0.57 (95% CI 0.38-0.86), and
0.57 (95% CI 0.38-0.84) for alpha-carotene, beta-carotene, and beta-cryptoxanthin,
respectively.
Conclusions: These
results provide little support for a cross-sectional association between angina
pectoris and serum and red blood cell folate concentrations or concentrations of
vitamins A, C, E, and B12. Several serum carotenoid concentrations were
associated with a reduced risk for angina pectoris, however.
Dietary
Flavonoids as Antioxidants in Vivo: Conjugated Metabolites of (-)-Epicatechin
and Quercetin Participate in Antioxidative Defense in Blood Plasma
Terao
J.
J Med Invest. 1999 Aug;46(3-4):159-168.
Flavonoids
are present in mainly plant foods and have attracted much attention in relation
to disease prevention. Their antioxidant activity at least partly accounts for
their potential health effect, because oxidative stress leads to a variety of
pathophysiological events. It is essential to know the bioavailability of
flavonoids involving intestinal absorption, metabolic conversion and urinary
excretion, in order to evaluate their in vivo antioxidant activity after intake.
Here (-)-epicatechin and quercetin were selected as typical flavanol- and
flavonol-flavonoids present in vegetables, fruits and tea. Our rat study
suggests that their metabolic conversion begins in the intestinal mucosa where
the activity of uridine-5'-diphosphoglucuronosyltransferase (UGT) is at its
highest. Both flavonoids accumulated mostly as glucuronide and sulfate
conjugates in blood plasma after oral administration. No intact quercetin was
found in the circulation. However, on the oral administration of these
flavonoids, the antioxidative ability of rat plasma was enhanced indicating that
conjugated metabolites participate in the antioxidant defense in blood plasma.
Therefore, the intake of vegetables, fruits and tea rich in flavonoids may help
to prevent oxidative damages in the blood.
Toward
a New Recommended Dietary Allowance for Vitamin C Based on Antioxidant and
Health Effects in Humans
Carr
AC, Frei B.
Am J Clin Nutr.
1999 Jun;69(6):1086-1087.
The
current recommended dietary allowance (RDA) for vitamin C for adult nonsmoking
men and women is 60 mg/d, which is based on a mean requirement of 46 mg/d to
prevent the deficiency disease scurvy. However, recent scientific evidence
indicates that an increased intake of vitamin C is associated with a reduced
risk of chronic diseases such as cancer, cardiovascular disease, and cataract,
probably through antioxidant mechanisms. It is likely that the amount of vitamin
C required to prevent scurvy is not sufficient to optimally protect against
these diseases. Because the RDA is defined as "the average daily dietary
intake level that is sufficient to meet the nutrient requirement of nearly all
healthy individuals in a group," it is appropriate to reevaluate the RDA
for vitamin C. Therefore, we reviewed the biochemical, clinical, and
epidemiologic evidence to date for a role of vitamin C in chronic disease
prevention. The totality of the reviewed data suggests that an intake of 90-100
mg vitamin C/d is required for optimum reduction of chronic disease risk in
nonsmoking men and women. This amount is about twice the amount on which the
current RDA for vitamin C is based, suggesting a new RDA of 120 mg vitamin C/d.
Alzheimer
Disease: Protective Factors
Nourhashemi
F, Gillette-Guyonnet S, Andrieu S, et al.
Am J Clin Nutr.
2000 Feb;71(2):643S-649S.
Approximately
6-8% of all persons aged >65 y have Alzheimer disease and the prevalence of
the disease is increasing. Any intervention strategy aimed at decreasing risks
or delaying the onset of the disease will therefore have a substantial effect on
health care costs. Nutrition seems to be one of the factors that may play a
protective role in Alzheimer disease. Many studies suggest that oxidative stress
and the accumulation of free radicals are involved in the pathophysiology of the
disease. Several studies have shown the existence of a correlation between
cognitive skills and the serum concentrations of folate, vitamin B-12, vitamin
B-6, and, more recently, homocysteine. However, nutritional factors have to be
studied not alone but with the other factors related to Alzheimer disease:
genetics, estrogen, antiinflammatory drug use, and socioeconomic variables. The
objective of this article was to review recent studies in this field.
Dietary
Factors in Relation to Rheumatoid Arthritis: A Role for Olive Oil and Cooked
Vegetables?
Linos
A, Kaklamani VG, Kaklamani E, et al.
Am J Clin Nutr.
1999 Dec;70(6):1077-1082.
Background:
Although several studies showed that risk of rheumatoid arthritis (RA) is
inversely associated with consumption of n-3 fatty acids, the one study showing
that olive oil may have a protective role has not yet been confirmed.
Objective: We
examined the relation between dietary factors and risk of RA in persons from
southern Greece.
Design: We studied
145 RA patients and 188 control subjects who provided information on demographic
and socioeconomic variables, prior medical and family history, and present
disease status. Subjects responded to an interviewer-administered, validated,
food-frequency questionnaire that assessed the consumption of >100 food
items. We calculated chi-square statistics for linear trend and odds ratios (ORs)
for the development of RA in relation to the consumption of olive oil, fish,
vegetables, and a series of food groups classified in quartiles.
Results: Risk of
developing RA was inversely and significantly associated only with cooked
vegetables (OR: 0.39) and olive oil (OR: 0.39) by univariate analysis. A
significant trend was observed with increasing olive oil (chi-square: 4.28; P =
0.03) and cooked vegetable (chi-square: 10. 48; P = 0.001) consumption. Multiple
logistic regression analysis models confirmed the independent and inverse
association between olive oil or cooked vegetable consumption and risk of RA
(OR: 0.38 and 0.24, respectively).
Conclusions:
Consumption of both cooked vegetables and olive oil was inversely and
independently associated with risk of RA in this population. Further research is
needed to elucidate the underlying mechanisms of this finding, which may include
the antioxidant properties or the high n-9 fatty acid content of the olive oil.
The
Influence of Chronic Yogurt Consumption on Immunity
Van
de Water J, Keen CL, Gershwin ME.
J Nutr. 1999 Jul;129(7 Suppl):1492S-1495S.
There
has been increased interest in the study of nutrition and immunity. This is
especially true with respect to the hypothesis that consumption of specific
foods may reduce an individual's susceptibility to the establishment and/or
progression of immunologic disease. Although an increased intake of a specific
food may improve health status in select cases, chronic consumption of large
amounts of one specific food may in fact be detrimental. The studies described
here examined the long-term effect of yogurt consumption on two different age
populations, young adults (20-40 y) and senior adults (55-70 y). There were
three study groups per age group, live-culture yogurt, pasteurized yogurt and
control (no yogurt), given 200 g/d of yogurt for 1 y. The subjects completed a
questionnaire detailing health parameters on a weekly basis and a 4-d food
record was taken monthly. Blood was taken every 3 mo and complete blood
chemistry, blood count, total and specific immunoglobulin (Ig)E, and
interferon-gamma (IFN-gamma) production measured.Yogurt consumption, especially
for the live-culture groups, was associated with a decrease in allergic symptoms
in both age groups. Seniors in the control group experienced an increase in both
total and LDL cholesterol, whereas those in the yogurt groups remained stable
during the course of the study. There was little effect on IFN-gamma and IgE
production, although seniors in the yogurt group had lower levels of total IgE
throughout the year.
Published
erratum appears in J Nutr.
1999 Oct;129(10):1932.
Yang
CS.
Nutrition. 1999 Nov-Dec;15(11-12):946-949.
The
possible beneficial effects of tea consumption in the prevention of cancer and
cardiovascular diseases have been demonstrated in animal models and suggested by
studies in vitro. Similar beneficial effects, however, have not been
convincingly demonstrated in humans: beneficial effects have been demonstrated
in some studies but not in others. If such beneficial effects do exist in
humans, they are likely to be mild, depending on many other lifestyle-related
factors, and could be masked by confounding factors in certain populations.
Another concern is that the amounts of tea consumed by humans are lower than the
doses required for demonstrating the disease-prevention effects in animal
models. Caution should be applied, however, in the use of high concentrations of
tea for disease prevention. Ingestion of large amounts of tea may cause
nutritional and other problems because of the caffeine content and the strong
binding activities of tea polyphenols, although there are no solid data on the
harmful effects of tea consumption. More research is needed to elucidate the
biologic activities of green and black tea and to determine the optimal amount
of tea consumption for possible health-beneficial effects.
Serum
Alpha-Tocopherol Status in the United States Population: Findings from the
Third National Health and Nutrition Examination Survey.
Ford
ES, Sowell A.
Am J Epidemiol.
1999 Aug 1;150(3):290-300.
Despite
the role vitamin E may have in protecting against various chronic conditions,
little is known about vitamin E status in the US population. Using data from the
Third National Health and Nutrition Examination Survey (1988-1994), the authors
examined the distribution and correlates of serum alpha-tocopherol among 16,295
US adults aged 18 or more years. The mean concentration of alpha-tocopherol was
26.8 micromol/liter (geometric mean, 25.0 micromol/liter). The 25th, 50th, and
75th percentiles were 19.6, 24.1, and 30.4 micromol/liter, respectively.The mean
alpha-tocopherol/cholesterol ratio was 5.1 (geometric mean, 4.9); the 25th,
50th, and 75th percentiles were 4.1, 4.7, and 5.5 (10(-3)), respectively. About
27% of the US population had a low alpha-tocopherol concentration (<20
micromol/liter). After age standardization, 29% of the men, 28% of the women,
26% of the whites (men, 27%, and women, 26%), 41% of the African Americans (men,
42%, and women, 40%), 28% of the Mexican Americans (men, 29%, and women, 27%),
and 32% of the other participants (men, 36%, and women, 29%) had this low
concentration. For all participants, age, educational attainment, serum
cholesterol, and several serum vitamins and carotenoids were directly related to
and high density lipoprotein cholesterol was inversely related to serum alpha-tocopherol
concentration in multiple linear regression analysis. Men had a higher
concentration than did women, and African Americans had the lowest concentration
of any racial or ethnic group. These results show that important proportions of
US adults have a low serum alpha-tocopherol concentration, which may increase
their risk for chronic diseases in which low dietary intake or blood
concentration of alpha-tocopherol have been implicated.