“Japanese people need more dietary intake of folate and vitamin B-6, which may lead to the prevention of heart disease,” said Hiroyasu Iso, M.D., professor of public health at Osaka University.

The findings on the value of B vitamins were consistent with studies in Europe and North America, although the dietary consumption of vitamin B-6 is generally lower in Japan than in the United States.

Researchers analyzed data from 23,119 men and 35,611 women (ages 40-79) who completed food frequency questionnaires as part of the large Japan Collaborative Cohort (JACC) Study. During a median 14 years of follow-up, 986 died from stroke, 424 from heart disease and 2,087 from all diseases related to the cardiovascular system.

Investigators divided participants into five groups based on their intake of folate, vitamin B-6 and vitamin B-12. Comparing those with the diets lowest and highest for each nutrient, they found that higher consumption of folate and vitamin B-6 was associated with significantly fewer deaths from heart failure in men, and significantly fewer deaths from stroke, heart disease and total cardiovascular diseases in women. Vitamin B-12 intake was not associated with reduced mortality risk.

The protective effects of folate and vitamin B-6 didn’t change when researchers adjusted for the presence of cardiovascular risk factors, nor when they eliminated supplement users from the analysis. Folate and vitamin B-6 may help guard against cardiovascular disease by lowering homocysteine levels, the investigators said. Homocysteine is an amino acid in the blood that’s affected by diet and heredity. Folic acid and other B vitamins help break down homocysteine in the body.

A direct causal link hasn’t been established, but evidence has shown that too much homocysteine may damage the inner lining of arteries and promote the formation of blood clots.

Sources of folate include vegetables and fruits, whole or enriched grains, fortified cereals, beans and legumes. Sources of vitamin B-6 include vegetables, fish, liver, meats, whole grains and fortified cereals.

Co-authors include: Renzhe Cui, M.D.; Chigusa Date, M.D.; Shogo Kikuchi, M.D.; Akiko Tamakoshi, M.D.; and the JACC study group. Author disclosures and funding sources are on the manuscript.

Source
American Heart Association

High-carbohydrate diets increase the levels of blood glucose and of harmful blood fats known as triglycerides while reducing levels of protective HDL or “good” cholesterol, thereby increasing heart disease risk, according to background information in the article. However, not all carbohydrates have the same effect on blood glucose levels. The glycemic index is a measure of how much a food raises blood glucose levels compared with the same amount of glucose or white bread. A related measure, the glycemic load, is calculated based on the glycemic index of a given food and also on the total amount of carbohydrates it contains.

Sabina Sieri, Ph.D., of Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy, and colleagues studied 47,749 Italian adults-15,171 men and 32,578 women-who completed dietary questionnaires. Based on their responses, the researchers calculated their overall carbohydrate intakes as well as the average glycemic index of the foods they consumed and the glycemic loads of their diets. During a median (midpoint) of 7.9 years of follow-up, 463 participants (158 women and 305 men) developed coronary heart disease.

The one-fourth of women who consumed the most carbohydrates overall had approximately twice the risk of heart disease as the one-fourth who consumed the least. When these carbohydrates were separated into high- and low-glycemic index categories, increased intake from high-glycemic index foods was significantly associated with greater risk of coronary heart disease, whereas low-glycemic index carbohydrates were not. “Thus, a high consumption of carbohydrates from high-glycemic index foods, rather than the overall quantity of carbohydrates consumed, appears to influence the risk of developing coronary heart disease,” the authors write.

The one-fourth of women whose diet had the highest glycemic load had 2.24 times the risk of heart disease compared with the one-fourth of women with the lowest glycemic load.

Overall carbohydrate intake, glycemic index and glycemic load were not associated with heart disease risk in men. This could be because the adverse changes associated with carbohydrate intake, including triglyceride levels, are stronger risk factors for heart disease in women than in men, the authors note.

“We tentatively suggest that the adverse effects of a high glycemic diet in women are mediated by sex-related differences in lipoprotein and glucose metabolism, but further prospective studies are required to verify a lack of association of a high dietary glycemic load with cardiovascular disease in men,” they conclude.

Arch Intern Med. 2010;170[7]:640-647.

Source
Archives of Internal Medicine

Research by Richard Mattes, professor of foods and nutrition, and his doctoral student, Corinna Alper, proves regular peanut consumption helps reduce the risk of cardiovascular disease without weight gain.

‘Peanuts are the most widely consumed nut in this country,’ Mattes said. ‘They are a rich source of monosaturated fatty acids, magnesium and folate, vitamin E, copper, arginine and fiber, all of which have cardiovascular disease risk-reducing properties.’

Mattes said the findings are consistent with several epidemiological and clinical studies.

‘Peanuts, which are actually legumes, are often viewed as unhealthy because they are high in fat,’ said Mattes. ‘This is the biggest obstacle in peanut consumption.

‘But peanuts are rich in the types of fats that actually reduce cardiovascular disease risk and have strong satiety properties – meaning a person feels full after eating peanuts – so they do not pose a threat of weight gain. People can feel comfortable including them in their diet to take advantage of peanuts’ reducing the risk of heart disease, without adding to body weight.’

Mattes and Alper conducted three trials in the study. The first trial entailed having participants reduce dietary fat intake by 500 calories and replace them with 500 calories of peanuts, so total calories did not change. Only the source of those calories did.

In the second trial, individuals consumed their regular diet and added 500 calories of peanuts, which boosted total caloric intake. In the third treatment, individuals were allowed to incorporate peanuts in their diets in any way they chose.

In all three groups, subjects’ triglyceride level – a risk factor for cardiovascular disease – was lowered significantly.

‘We have learned that regular peanut consumption lowers triglyceride levels by as much as 24 percent – even in the group where peanuts were added to regular dietary intake,’ Mattes said. ‘We also saw no significant change in body weight, despite adding 500 calories of peanuts a day for eight weeks.

‘Of course, we want to know where those calories went. There are three possible answers to that question.’

The first is that peanuts have a high satiety value, and that feeling of being full reduces the amount a person eats. Mattes said this accounts for the largest portion of missing calories.

The second possibility is that the peanuts trigger an increase in people’s resting metabolic rate. The third explanation is that people don’t chew nuts well, so people’s bodies fail to absorb a portion of nuts’ caloric energy.

‘There is great public health significance to work in this area,’ Mattes said. ‘This particular study indicates it may be an appropriate health recommendation to include peanuts in the daily diet.’

The study was funded by a grant from the United States Agency for International/National Development.

Mattes’ team also conducts research in Ghana and Brazil, so he sees the peanut research findings have global value. ‘There is great opportunity for the peanut industry in developing countries,’ Mattes said. ‘Peanuts have a long shelf life and are rich in nutrients.’

Mattes’ study, ‘Peanut Consumption Improves Indices of Cardiovascular Disease Risk in Healthy Adults, ‘ was published in the April 2003 issue of the Journal of American College of Nutrition. In addition to this study, Mattes is doing research on identifying how the energy from peanuts is used and whether the healthful properties of peanuts are due to their oil content.

Writer: Amy Patterson-Neubert, (765) 494-9723, apatterson@purdue.edu

Source: Richard Mattes, (765) 494-0662, mattesr@cfs.purdue.edu

Purdue News Service: (765) 494-2096; purduenews@purdue.edu

ABSTRACT

Peanut Consumption Improves Indices of Cardiovascular Disease Risk in Healthy Adults

Corinna A. Alper and Richard D. Mattes

Diets containing nuts reduce cardiovascular disease risk factors. This has primarily been attributed to their fatty acid compensation, but other constituents may also contribute.

Peanuts, the most widely consumed nut (actually a legume), are a rich source of monosaturated fatty acids, magnesium and folate, but their effects on cardiovascular disease risk factors are poorly characterized. This study determined the effects of chronic peanut consumption on diet composition as well as serum lipids, magnesium and homocysteine concentrations in free-living subjects under different conditions of peanut intake. Regular peanut consumption lowers serum triacylglycerol, augments consumption of nutrients associated with reduced cardiovascular disease risk and increases serum magnesium concentrations.

For decades, scientists have had inklings that a diet that derives about 40 percent of its calories from healthy fat and about half from complex carbohydrates such as whole grains, fruit and vegetables, combined with daily exercise, could promote health and reduce premature death.

But this is the first large trial of healthy men and women to demonstrate a significant reduction in death rates for heart disease, cancer and all other causes of mortality for those who follow a Mediterranean diet and are physically active.

‘In the past, when we talked about the Mediterranean diet, we usually talked about cardiovascular benefits,’ Frank Hu, associate professor of nutrition and epidemiology at the Harvard School of Public Health, said yesterday. ‘This is talking about primary prevention. The better the Mediterranean diet, the lower the cardiovascular disease and cancer mortality. . . . That is very intriguing.’

The results suggest a middle course between the often confusing diet extremes, from the very low-carbohydrate, high-fat Atkins approach to the higher carbohydrate, low-fat U.S. dietary guidelines.

The findings also point to ‘diet as being very important in more ways than we had anticipated,’ said Walter Willett, chairman of the department of nutrition at the Harvard School of Public Health, who advocates boosting ‘healthy fat’ in the American diet as well as adding more grains, fruit, vegetables and fish. (So-called healthy fats are found in such foods as olive oil, avocados, nuts, and fish.)

The U.S government’s recommendation of consuming only 30 percent total fat may ‘not be optimal for many people,’ Willett said. But the study also ‘emphasizes that for overall good health, eating porterhouse steak, butter and lard is not the way to go.’

What the results also underscore is the importance of the overall Mediterranean diet approach, rather than any one food type. In an article that accompanies the results, which are published in today’s New England Journal of Medicine, Hu suggests that this could be explained in two ways: either the effects of any one nutrient are too small to detect, or there may be synergistic effects of the Mediterranean diet that are important.

‘That’s interesting,’ Willett said, ‘because any one piece of the Mediterranean diet on its own was not so impressive. It’s the whole package — the fruit and vegetables, the nuts . . . all those things that seem to contribute.’

The study involved 22,043 adults, ages 20 to 86, who live in Greece; people with diabetes and known heart disease were excluded.

Upon entering the study, participants were interviewed in depth about their daily diets and exercise habits. The researchers assigned points for each component of diet and lifestyle.

For example, eating vegetables, legumes and beans, fruit, nuts, whole grains (in cereal, bread and pasta) and fish raised the scores. So did consuming more monounsaturated fats, such as olive oil, rather than saturated fats, such as butter or cream.

Participants also received a point for drinking moderate amounts of alcohol — about a glass of wine a day for women; two glasses for men — but got a zero if they imbibed more or less than that.

Regularly eating meat, poultry, sweets and dairy products, which in Greece are generally high in saturated fat, added no points and resulted in a lower overall diet score.

The research team, which was led by Antonia Trichopoulou of the University of Athens Medical School and Dimitrios Trichopoulos of the Harvard School of Public Health, then tracked participants for an average of nearly four years.

They also took into account age, sex, years of education, smoking status, body mass index (to gauge overweight and obesity) and waist-to-hip ratios, which help determine risk for heart disease and diabetes.

The study found that the higher the healthy diet score, the lower the risk of death. For every two-point rise — achieved, for example, by eating a lot of vegetables and consuming beans and nuts daily — the risk of death dropped by 25 percent, the study found.

‘This says you can get tremendous benefit from simply moving away from unhealthy foods, and there are multiple ways that you can achieve this,’ Hu said.

Daily physical activity also played a critical role in reducing mortality from heart disease and cancer, the study found. People who engaged in at least an hour a day of very vigorous activity, either on the job or at leisure, had a 28 percent reduced risk of mortality compared with their more sedentary counterparts.

The effects of physical activity ‘cannot be overemphasized,’ Hu said.

The findings echo the results of smaller studies, including the Lyon Diet Heart Study in France, that have hinted at health benefits of the Mediterranean lifestyle.

In the Lyon trial, researchers randomly assigned 605 people diagnosed with heart disease to either follow a Mediterranean-style diet or the American Heart Association diet, which has about 30 percent of calories from fat, including 10 or less from saturated fat.

In this study, people assigned to the Mediterranean group were encouraged to eat more fruit, vegetables and fish, to cut back on red meat and to use olive oil instead of butter and cream.

The study found that the Mediterranean diet group suffered 73 percent fewer heart attacks or other heart-related problems and had 70 percent fewer deaths than those on the heart association diet.