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Biomedical subjects

N D Barnard

Publications and source records attributed to N D Barnard.

At least 19 recordsLinked to original sources
PubMed2000

Effectiveness of a low-fat vegetarian diet in altering serum lipids in healthy premenopausal women.

Few controlled trials have studied cholesterol-lowering diets in premenopausal women. None has examined the cholesterol-lowering effect of a low-fat vegetarian diet, which, in other population groups, leads to marked reductions in serum cholesterol concentrations and, in combination with other life-style changes, a regression of atherosclerosis. We tested the hypothesis that a low-fat, vegetarian diet significantly reduces serum total and low-density lipoprotein (LDL) cholesterol concentrations in premenopausal women. In a crossover design, 35 women, aged 22 to 48, followed a low-fat vegetarian diet deriving approximately 10% of energy from fat for 2 menstrual cycles. For 2 additional cycles, they followed their customary diet while also taking a "supplement" (placebo) pill. Serum lipid concentrations were assessed at baseline and during each intervention phase. Mean serum LDL, high-density lipoprotein (HDL), and total cholesterol concentrations decreased 16. 9%, 16.5%, and 13.2%, respectively, from baseline to the intervention diet phase (p<0.001), whereas mean serum triacylglycerol concentration increased 18.7% (p<0.01). LDL/HDL ratio remained unchanged. Thus, in healthy premenopausal women, a low-fat vegetarian diet led to rapid and sizable reductions in serum total, LDL, and HDL cholesterol concentrations.

Adult↗
PubMed2000

Diet and sex-hormone binding globulin, dysmenorrhea, and premenstrual symptoms.

OBJECTIVE: To test the hypothesis that a low-fat, vegetarian diet reduces dysmenorrhea and premenstrual symptoms by its effect on serum sex-hormone binding globulin concentration and estrogen activity. METHODS: In a crossover design, 33 women followed a low-fat, vegetarian diet for two menstrual cycles. For two additional cycles, they followed their customary diet while taking a supplement placebo pill. Dietary intake, serum sex-hormone binding globulin concentration, body weight, pain duration and intensity, and premenstrual symptoms were assessed during each study phase. RESULTS: Mean (+/- standard deviation [SD]) serum sex-hormone binding globulin concentration was higher during the diet phase (46.7 +/- 23.6 nmol/L) than during the supplement phase (39.3 +/- 19.8 nmol/L, P < .001). Mean (+/- SD) body weight was lower during the diet (66.1 +/- 11.3 kg) compared with the supplement phase (67.9 +/- 12.1 kg, P < .001). Mean dysmenorrhea duration fell significantly from baseline (3.9 +/- 1.7 days) to diet phase (2.7 +/- 1.9 days) compared with change from baseline to supplement phase (3.6 +/- 1.7 days, P < .01). Pain intensity fell significantly during the diet phase, compared with baseline, for the worst, second-worst, and third-worst days, and mean durations of premenstrual concentration, behavioral change, and water retention symptoms were reduced significantly, compared with the supplement phase. CONCLUSION: A low-fat vegetarian diet was associated with increased serum sex-hormone binding globulin concentration and reductions in body weight, dysmenorrhea duration and intensity, and premenstrual symptom duration. The symptom effects might be mediated by dietary influences on estrogen activity.

Adolescent↗
PubMed1999

Toward improved management of NIDDM: A randomized, controlled, pilot intervention using a lowfat, vegetarian diet.

OBJECTIVE: To investigate whether glycemic and lipid control in patients with non-insulin-dependent diabetes (NIDDM) can be significantly improved using a low-fat, vegetarian (vegan) diet in the absence of recommendations regarding exercise or other lifestyle changes. METHODS: Eleven subjects with NIDDM recruited from the Georgetown University Medical Center or the local community were randomly assigned to a low-fat vegan diet (seven subjects) or a conventional low-fat diet (four subjects). Two additional subjects assigned to the control group failed to complete the study. The diets were not designed to be isocaloric. Fasting serum glucose, body weight, medication use, and blood pressure were assessed at baseline and biweekly thereafter for 12 weeks. Serum lipids, glycosylated hemoglobin, urinary albumin, and dietary macronutrients were assessed at baseline and 12 weeks. RESULTS: Although the sample was intentionally small in accordance with the pilot study design, the 28% mean reduction in fasting serum glucose of the experimental group, from 10.7 to 7.75 mmol/L (195 to 141 mg/dl), was significantly greater than the 12% decrease, from 9.86 to 8.64 mmol/L (179 to 157 mg/dl), for the control group (P < 0.05). The mean weight loss was 7.2 kg in the experimental group, compared to 3. 8 kg for the control group (P < 0.005). Of six experimental group subjects on oral hypoglycemic agents, medication use was discontinued in one and reduced in three. Insulin was reduced in both experimental group patients on insulin. No patient in the control group reduced medication use. Differences between the diet groups in the reductions of serum cholesterol and 24-h microalbuminuria did not reach statistical significance; however, high-density lipoprotein concentration fell more sharply (0.20 mmol/L) in the experimental group than in the control group (0.02 mmol/L) (P < 0.05). CONCLUSION: The use of a low-fat, vegetarian diet in patients with NIDDM was associated with significant reductions in fasting serum glucose concentration and body weight in the absence of recommendations for exercise. A larger study is needed for confirmation.

Adult↗
PubMed1999

Racial bias in federal nutrition policy, Part I: The public health implications of variations in lactase persistence.

The Dietary Guidelines for Americans from the basis for all federal nutrition programs and incorporate the Food Guide Pyramid, a tool to educate consumers on putting the Guidelines into practice. The Pyramid recommends two to three daily servings of dairy products. However, research has shown that lactase nonpersistence, the loss of enzymes that digest the milk sugar lactose, occurs in a majority of African-, Asian-, Hispanic-, and Native-American individuals. Whites are less likely to develop lactase nonpersistence and less likely to have symptoms when it does occur. Calcium is available in other foods that do not contain lactose. Osteoporosis is less common among African Americans and Mexican Americans than among whites, and there is little evidence that dairy products have an effect on osteoporosis among racial minorities. Evidence suggests that a modification of federal nutrition policies, making dairy-product use optional in light of other calcium sources, may be a helpful public health measure.

Adolescent↗
PubMed1999

Racial bias in federal nutrition policy, Part II: Weak guidelines take a disproportionate toll.

Many diet-related chronic diseases take a disproportionate toll among members of racial minorities. Research shows the prevalence of diabetes, hypertension, cancer, and heart disease is higher among various ethnic groups compared with whites. The Guidelines and the Food Guide Pyramid, however, promote the use of multiple servings of meats and dairy products each day and do not encourage replacing these foods with vegetables, legumes, fruits, and grains. The Dietary Guidelines for Americans encourage a 30% caloric reduction in fat intake and make no provision for further reductions for those who wish to minimize health risks. Abundant evidence has shown that regular exercise combined with diets lower in fat and richer in plant products than is encouraged by the Dietary Guidelines for Americans are associated with reduced risk of these chronic conditions. While ineffective Dietary Guidelines potentially put all Americans at unnecessary risk, this is particularly true for those groups hardest hit by chronic disease.

Cerebrovascular Disorders↗
PubMed1995

Factors that facilitate compliance to lower fat intake.

The success of dietary interventions that are prescribed to reduce the risk of heart disease depends on the degree to which patients actually change their diets. A review of research trials using different diets and various means of fostering dietary change to reduce cardiac risk factors identified specific factors that are associated with a greater degree of dietary change. Contrary to the common conception that strict diets are unacceptable to patients, those research studies that set stricter limits on fat intake achieved a greater degree of dietary change than did studies with more modest goals. Additional factors used by studies that achieved a lower fat intake include monitoring dietary intake at least monthly, family involvement, group support, provision of food, initial residential treatment, the use of vegetarian diets, and symptomatic subjects. These factors may be useful to researchers and to clinicians seeking to improve dietary compliance in patients.

Cardiovascular Diseases↗
PubMed1995

The medical costs attributable to meat consumption.

OBJECTIVE: To estimate the medical costs that are attributable to the health effects of meat consumption. METHODS: The prevalence of hypertension, heart disease, cancer, diabetes, gallstones, obesity, and foodborne illness among omnivores and vegetarians are compared in studies that have controlled for other lifestyle factors, and the corresponding attributable medical costs are calculated in 1992 dollars. RESULTS: Direct health care costs attributable to meat consumption are estimated to be +2.8-8.5 billion for hypertension, +9.5 billion for heart disease, +0-16.5 billion for cancer, +14.0-17.1 billion for diabetes, +0.2-2.4 billion for gallbladder disease, +1.9 billion for obesity-related musculoskeletal disorders, and +0.2-5.5 billion for foodborne illness. The total direct medical costs attributable to meat consumption for 1992 are estimated at +28.6-61.4 billion. CONCLUSION: Health care costs attributable to meat consumption are quantifiable and substantial.

Adult↗
PubMed1990

Animal rights.

Explore the source record for details and available documents.

Animal Welfare↗
PubMedDate not supplied

Beliefs about dietary factors in breast cancer prevention among American women, 1991 to 1995.

OBJECTIVE: To estimate the percentage of American women in various demographic groups who believe or have heard that dietary factors have a role in breast cancer prevention and to assess changes between 1991 and 1995. METHODS: Telephone surveys were conducted of random samples of 509 women in 1991 and 510 women in 1995. Subjects were asked questions with increasing prompting to gauge their beliefs about the role of dietary factors in breast cancer prevention. RESULTS: The percentages of women citing dietary factors (reducing intake of fat or meat or increasing intake of vegetables, fruit, fiber, or vegetarian meals) as reducing the risk of developing breast cancer were 20% in 1991 and 23% in 1995. These numbers were lower among young, poor, and less educated women. When specifically prompted to consider dietary steps, the number citing such factors increased to 37% in 1991 and to 52% in 1995. CONCLUSION: The belief that there is a role for dietary factors in breast cancer is far from universal among American women, although some measures of the awareness of dietary factors increased significantly between 1991 and 1995. Women are more likely to cite mammography and breast self-examination as preventive steps, even though both are designed for detection rather than prevention. Additional efforts are needed to provide information on cancer prevention, particularly to young, poor, and less educated women, and to clarify the role of prevention as distinct from cancer detection.

Adult↗