CONTENTS

" Is dietary fat a major determinant of body fat" ?

Functional foods in the prevention and treatment of disease: significance of the Dietary Approaches to Stop Hypertension Study

Dietary Guidelines Around the World

Peanut Oil - A Healthy Oil ?

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TOP NUTRITION NEWSLETTER

VOLUME 1, NO 9: SEPTEMBER 1998

Editorial

This is the ninth issue of TOP NUTRITION NEWSLETTER in 1998.In this issue, dietary fat and obesity, functional foods for hypertension, and dietary guidelines are updated for your interest.

Nutrition research cannot improve poeple's health until the results influence their purchases and consumption of food and drink. Nowadays insufficient or conflicting public information on food should be critically evaluated by a well-balanced expert committee. In developed countries, coronary artery disease mortality has declined but obesity has increased. This is the time to evaluate whether the percentage of fat energy is a major determinant of body fat.Let's observe the massive increase in obesity in the United States after a substantial decline in the percentage of fat energy consumed during the past two decades. Could we answer " Is dietary fat a major determinant of body fat" ?

Functional foods in the prevention and treatment of disease: significance of the Dietary Approaches to Stop Hypertension Study (DASH Study) used a diet which contained double the amount of fruit and vegetables and low-fat dairy products usually eaten in the USA. When people with high blood pressure ate this diet for 8 weeks, their systolic blood pressure
dropped by up to 11.4 mm Hg and diastolic blood pressure decreased by up to 5.5 mm Hg. Such changes in blood pressure can usually only be achieved with antihypertensive drugs. The fact that the DASH Diet can lower blood pressure is welcome news.The DASH Diet consists of grains & cereals (energy & dietary fiber), vegetables & fruits (dietary fiber, potassium, magnesium), low-fat dairy products (protein & calcium), meat, fish & poultry (protein & magnesium) , and nuts (dietary fiber & protein) and the critical point is how to adjust these food.

Dietary Guideline is one of the important issues for the Public Health Services in every country. International Food Information Council has updated the food issues worldwide. March/April 1998 issue of Food Insight has interesting topic on " Dietary Guidelines Around the World " . Please update your knowledge about the dietary guidelines.

Dietary oils for cooking vary around the world not even the neighbouring countries like Thailand and Burma. Which oil is the best for cooking ? This question was asked to me several times. Canola oil....olive oil.....rice bran oil.....peanut oil.....but not soybean oil or palm oil. Please do not misunderstand me. The choice is just my choice , not others. I like the taste and smell of canola oil, olive oil, and peanut oil. According to the situation, I could not use my favorites for cooking but rice bran oil (RBO) for economical reason. This is the IMF era. We need to be cost-effective in preventing the ischemic heart disease which averages 95 per 100,000 population. Rice bran oil, a so-called "healthy oil" has ~ 40% linoleic acid, ~ 40% oleic acid, ~ 3% alpha-linolenic acid. The hypocholesterolemic effect of RBO may be due to high oleic acid, gamma-oryzanol, and tocotrienols. Canola oil, olive oil and peanut oil also has similar hypocholesterolemic effect which may be due to high oleic acid. Please check the composition of dietary oils available and give your opinion about your favorite dietary oil after reading Peanut Oil - A Healthy Oil ?

Although I have selected only the most interesting and reliable sources for you, you may have different opinions. If you would like to read any interesting topics, please do not hesitate to e-mail me.

Happy Reading.

Dr Shwe Win

Editor

Is dietary fat a major determinant of body fat?

Walter C Willett
Source: Am J Clin Nutr 1998;67(suppl):556S-62S.

The percentage of energy from dietary fat is widely believed to be an important determinant of body fat, and several mechanisms have been proposed to account for such a relation. Comparisons of both diets and the prevalence of obesity between affluent and poor countries have been used to support a causal association, but these contrasts are seriously confounded by differences in physical activity and food availability. Within areas of similar economic development, regional intake of fat and prevalence of obesity have not been positively correlated. Randomized trials are the preferable method to evaluate the effect of dietary fat on adiposity, and are feasible because the number of subjects needed is not large. In short-term trials, a modest reduction in body weight is typically seen in individuals randomly assigned to diets with a lower percentage of energy from fat. However, compensatory mechanisms appear to operate because in trials lasting 1 y, fat consumption within the range of 18--40% of energy appears to have little if any effect on body fatness. Moreover, within the United States, a substantial decline in the percentage of energy from fat consumed during the past two decades has corresponded with a massive increase in obesity. Diets high in fat do not appear to be the primary cause of the high prevalence of excess body fat in our society, and reductions in fat will not be a solution.

This review article discussed the empirical evidence (between-population and within-population studies), randomized trials, short-term weight-loss trials, and interventional trials.In short-term studies, a modest reduction in body weight is typically seen in individuals assigned to diets with a lower percentage of energy from fat. Howeve, compensatory mechanisms appear to operate such that in the longer term, fat consumption within the range of 18-40% of energy appears to have little if any effect on body fatness. The nature of these compensatory mechanisms is presently unknown. In historical data, (for example, Japan) traditional low-fat diets have related to low incidence of obesity. The possibility that individuals vary in their susceptibility to high-fat or high-carbohydrate diets deserves further examinations. If the high-fat diets are not the cause of obesity, low level of physical activity may be the culprit. Next question should be whether we do need to change the energy requirements to prevent or treat the rising obesity.

Functional foods in the prevention and treatment of disease: significance of the Dietary Approaches to Stop Hypertension Study

G L Blackburn
Source: American Journal of Clinical Nutrition. 1997; 66: 1067-1071

Eastern traditional medicine has been using nutritional remedies to promote health and treat disease for millennia. The West has always been sceptical about this approach. Recently, however, there has been a change in attitude. Thanks to the efforts of the Institute of Food Technologists, and the International Life Sciences Institute (ILSI), a more positive attitude towards the use of so-called Functional Foods to treat and prevent diseases, is emerging in western scientific circles.

The Dietary Approaches to Stop Hypertension (DASH) Study is the first prospective, randomised trial which is investigating the use of fruit and vegetables, and low-fat dairy products at a level of twice that of the normal consumption in the USA, to achieve reductions in blood pressure as
effectively as those obtained with standard drug treatments. In the DASH Study, subjects with high normal and stage 1 hypertension, were either randomly assigned to a control diet low in
fruit, vegetables and dairy products, with a fat content equal to the typical American diet, or a diet rich in fruit and vegetables, or a diet rich in both fruit and vegetables and low-fat dairy products (the DASH diet), for a period of 8 weeks. In the DASH diet group, average systolic and diastolic blood pressure decreased by 5.5 mm and 3.0 mm Hg, respectively, compared to the control diet group. Subjects with stage 1 hypertension had the most significant decreases in blood pressure,
namely 11.4 and 5.5. mm Hg for systolic and diastolic blood pressure, respectively. Such decreases are comparable with decreases achieved with antihypertensive drugs. The improvement in blood pressure readings were evident after two weeks of the DASH diet, and it persisted for the whole length of the study.

The McCarron Study which used the principles of balanced nutrition to achieve prophylactic outcomes, was conducted by McCarron and coworkers (1997). Participants in this study were supplied with a prepacked optimal diet, which contained all the vitamins, minerals and macronutrients recommended by the US National Research Council. This was a 10 week
randomised, multi-centre, parallel-intervention study carried out with 560 men and women in 10 medical centres throughout the USA and Canada. Subjects had hypertension, and dyslipidaemia, or diabetes, or both diseases. Compared to self-selected American Heart Association step 1 and step 2 diets, (the control diets), the optimal prepackaged diet achieved improvements in blood pressure, lipid levels, carbohydrate metabolism, body weight and quality of life (P<0.001), for all variables, except the ratio of LDL:HDL. Use of the prepared foods provided the following beneftis:
(1) increased clinical improvements (2) balanced nutritional intake (3) greater patient compliance
(4) tasty, convenient meals which fitted in with modern eating trends in the USA and Canada

The author points out that both these studies were relatively short (8 and 10 weeks), and that the next step in the investigation of the use of functional foods to treat and prevent diseases, will have to include long-term studies. In regard to the DASH diet, the author stresses that it requires a number of dietary changes that some people may find difficult, e.g. doubling of fruit, vegetable and low-fat dairy product intake, decrease in meat intake by one third, cutting fats and oils intake by half, and reducing typical intake of sweets and snacks to one quarter of normal intake.

Most people will most probably opt for swallowing a blood pressure or lipid-lowering pill instead. This is a pity when the answer to so many diseases lies in balanced eating. However, with the urgent need in countries around the world to cut back on the cost of health care, the dietary option may be the only one left to us. The author concludes this stimulating paper by saying that, "Never before has the focus on the health benefits of commonly available foods been so strong. The philosophy that food can be health promoting beyond its nutritional value is gaining acceptance within both the public arena and the scientific community." He encourages researchers to intensify their efforts to discover the benefits of diet, and to change western attitudes to the use of food to treat and prevent ills health.

Dietary Guidelines Around the World

IFIC
Source: Food Insight March/April 1998.

1995 DIETARY GUIDELINES FOR AMERICANS

Eat a variety of foods
Balance the food you eat with physical activity
Maintain or improve your weight
Choose a diet with plenty of grain products, vegetables and fruits
Choose a diet low in fat, saturated fat and cholesterol
Choose a diet moderate in sugars
Choose a diet moderate in salt and sodium
If you drink alcoholic beverages, do so in moderation
(Source: U.S. Department of Agriculture / U.S. Department of Health and Human Services)



Most Americans are aware that they need to eat a variety of foods, moderate their fat intake and increase physical activity, because they have been hearing these messages for decades. The Dietary Guidelines for Americans were first published in 1980 by the U.S. Department of Agriculture and U.S. Department of Health and Human Services. They provide general nutrition guidance, emphasizing optimal intake of essential vitamins and minerals to prevent chronic diseases. The principles of these guidelines are used by policymakers in developing health guidelines and by health professionals for patient education.

Dietary guidelines are suggestions for people to follow based on nutritional needs, food supplies and cultural lifestyles. These guidelines are intended to be applied to the whole diet, and not to assess the healthfulness of any individual food.

Even as eating practices and lifestyles differ throughout the world, dietary guidance has surprising similarities, from the United States to Thailand to Israel. Whether a country supports three guidelines or fifteen, there are similar, basic recommendations shared throughout the world.

Eat a variety of foods
Overwhelmingly, the most consistent message across worldwide dietary guidance is "variety," and it is usually the premiere guideline. Japanese guidelines are even more specific and they recommend eating at least 30 different foods each day to achieve variety.

Eat a diet low in fat
As chronic diseases such as heart disease and diabetes spread into every world culture, dietary advice includes messages about fat, saturated fat and cholesterol. However, the level of recommended consumption, particularly for total fat, varies greatly across the world. Korean guidelines recommend "keeping fat consumption at 20 percent of energy intake," while the
Netherlands recommends a higher level at 35 percent of total energy intake.

Achieving and maintaining an appropriate weight & physical activity
Many countries recognize the importance of appropriate body weight and balancing "energy in" with "energy out." However, different messages are used to communicate this concept. Some countries, like Japan, advocate balance -- "Take energy corresponding to daily activity," while others, for example the United Kingdom, focus on weight -- "Eat the right amount to be a
healthy weight." A few countries currently mention "physical activity."

Moderating sodium and sugar intake
Moderation of sodium, or salt, intake is included in several countries' guidelines. Many countries do not quantify levels of recommended intake; however, those that do, range from 4.5 grams of salt a day (Singapore) to 10 grams of salt a day (Japan).

While some guidelines mention sugars, most countries do not quantify recommended sugars intake. Canada, Korea, Japan and the Philippines do not mention sugars at all in their guidelines.

Alcohol consumption
Most countries mention alcohol, and moderation is a key term used for these recommendations. Messages range from "If you drink, keep within sensible limits," in the United Kingdom, to "Alcohol is forbidden for children and pregnant women," in Hungary.

Enjoy the food

Diets and food supplies, like cultures and lifestyles, differ throughout the world, so it is natural that some dietary guidelines vary. These differences are likely to occur depending on how the dietary guidance is utilized, for example, policy makers using them to define and set standards, or as a basis for public education on nutrition and health. Enjoyment of eating Many nations' dietary guidelines recognize that eating is more than just nutrition -- food is a pleasure and
has strong links to family, traditions and culture. This is illustrated by the United Kingdom's first dietary guideline -- "Enjoy your food." French guidelines also emphasize the enjoyment of eating -- a prevalent part of their culture. The second French guideline recommends eating "three good meals each day." In Japan, dietary guidelines promote culture and family values. Eating together as a family is an occasion for happiness and promotes cultural tradition.


J A P A N

Obtain well-balanced nutrition with a variety of foods; eat 30 foodstuffs a day; take staple food, main dish and side dish together. Take energy corresponding to daily activity. Consider the amount and quality of the fats and oils you eat: avoid too much, eat more vegetable oils than animal fat. Avoid too much salt, not more than 10 grams a day. Happy eating makes for happy family life; sit down and eat together and talk; treasure family taste and home cooking.


Similarly, Vietnamese guidelines recommend "a healthy family meal that is delicious, wholesome, clean and economical, and served with affection."

Quantitative recommendations
The United States' guidelines have a broader purpose than simply policy development; they also are communicated to the American public.Beginning in the 1990s, it was quantified the recommended amount of daily fat intake in the Dietary Guidelines.But, in some countries levels are set for fat, sodium, carbohydrate and sugar intake. The dietary guidelines of the Netherlands,
for example, are very specific about individual nutrients and foods compared to other countries.

T H E N E T H E R L A N D S

Achieve or maintain a normal body weight
Balance the diet; supply adequate amounts of all essential nutrients
Ensure an average total fat intake of 30-35% of dietary energy
Make sure that saturated fat consumption is around 10% of total energy and polyunsaturated fat is 50 to 100% of saturated fat
Do not let dietary cholesterol exceed 33mg/MJ*
Maintain carbohydrate consumption at 50-60% of energy; sugars 15-25% energy
Maintain protein consumption at 10-25% of energy
Eat dietary fiber, target 3 gm/MJ
Realize that current alcohol consumption is far too high in many cases
Eat no more than 8 gm salt per day
* MJ = European measurement of food energy


N O R W A Y

FOOD + JOY = HEALTH
National Nutrition Council,
Norway

T H A I L A N D

A happy family is when family members eat together, enjoy treasured family tastes and good home cooking.
Reference: "A guide for daily food consumption," Thailand


The countries in North America, Europe and Asia have had dietary guidelines for their populace for over a decade. And, developing countries have an increasing need for dietary guidance as obesity and chronic disease rates rise. Smaller countries such as Fiji and the Philippines have already set dietary guidelines for the health and well-being of their populace.

Peanut Oil - A Healthy Oil ?

Source: Personnel Communication, Data in File,1998

Comparisons of Composition of Peanut Oil and Rice Bran Oil

AHA Scientific Position

There are three kinds of fats in the foods we eat: saturated, polyunsaturated and monounsaturated fatty acids. Most foods contain all three types of fat, but in varying amounts. Only saturated fatty acids and dietary cholesterol raise blood cholesterol. A high level of cholesterol in the blood is a major risk factor for coronary heart disease (which leads to heart attack).

AHA Recommendation

· The body can use all three types of fats, but the American Heart Association recommends that the average person should limit total fat intake to no more than 30 percent of total calories.

· Of that amount, you should limit your saturated fatty acid intake to 8–10 percent of total calories each day.

· The American Heart Association recommends that you consume polyunsaturated fatty acids up to 10 percent of your total calories.

· Monounsaturated fatty acid intake should be up to 15 percent of total calories.

What are recommended amounts of total fat and saturated fat in grams?

What are saturated fatty acids?

Saturated fatty acids have all the hydrogen the carbon atoms can hold. Saturated fats are usually solid at room temperature, and they are more stable — that is, they do not combine readily with oxygen. Saturated fatty acids are the main dietary culprit in raising blood cholesterol. The main sources of saturated fatty acids in the typical American diet are foods from animals and some plants.

· Foods from animals that have high amounts of saturated fatty acids include beef, beef fat, veal, lamb, pork, lard, poultry fat, butter, cream, milk, cheeses, and other dairy products made from whole milk. These foods also contain dietary cholesterol.

· Foods from plants that contain high amounts of saturated fatty acids include coconut oil, palm oil and palm kernel oil (often called tropical oils), and cocoa butter.

What about hydrogenated fats?

During food processing, fats may undergo a chemical process known as hydrogenation . Hydrogenate means to add hydrogen, or, in the case of fatty acids, to saturate. The process changes a liquid oil, naturally high in unsaturated fatty acids, to a more solid and more saturated form. The greater the degree of hydrogenation, the more saturated the fat becomes. Many commercial products contain hydrogenated or partially hydrogenated vegetable oils.

Recent studies suggest that these fats may raise blood cholesterol. Hydrogenated fats in margarine and other fats are acceptable if the product contains liquid vegetable oil as the first ingredient and no more than 2 grams of saturated fatty acids per tablespoon. The fatty acid content of most margarines and spreads is printed on the package or label.

What are polyunsaturated and monounsaturated fatty acids?

Polyunsaturated and monounsaturated fatty acids make up the total of unsaturated fatty acids. Unsaturated fatty acids have at least one unsaturated bond — that is, at least one place that hydrogen can be added to the molecule. They are often found in liquid oils of vegetable origin.

· Polyunsaturated oils are liquid at room temperature and in the refrigerator. They easily combine with oxygen in the air to become rancid. Common sources of polyunsaturated fatty acids are safflower, sesame and sunflower seeds, corn and soybeans, many nuts and seeds, and their oils.

· Monounsaturated oils are liquid at room temperature but start to solidify at refrigerator temperatures. Canola, olive and peanut oils and avocados are sources of monounsaturated fatty acids.

Polyunsaturated fatty acids tend to help the body get rid of newly formed cholesterol. Thus, they keep the blood cholesterol level down and reduce cholesterol deposits in artery walls. Recent research has shown that monounsaturated fatty acids may also help reduce blood cholesterol as long as the diet is very low in saturated fat.

Both types of unsaturated fatty acids may help lower your blood cholesterol level when used in place of saturated fatty acids in your diet. But you should be moderate in your intake of all types of fat.

Poly- or monounsaturated oils — and margarines and spreads made from these oils — should be used in limited amounts in place of fats with a high saturated fatty acid content, such as butter, lard or hydrogenated shortenings.

When was the last time you had a peanut butter and jelly sandwich? You may have been one of those children who ate those sandwiches almost every day of childhood. Yet, many adults stay away from peanut butter, a handful of peanuts at a party or peanut oil in a salad dressing because of fears of dietary fat levels. Now, new research released in April 1998 at the Experimental Biology '98 meeting in San Francisco shows it may actually be beneficial to your heart health to add these items to the diet.

The researchers found that diets containing peanuts, peanut butter or peanut oil are as effective as diets high in olive oil in protecting against heart disease. In fact, the results indicated diets containing peanut products are more effective in protecting against heart disease than are very low-fat diets. A total of 22 healthy men and women ages 21-54--many of whom had slightly elevated blood cholesterol levels at the beginning of the study--participated in the research. Each participant was randomized into one of five diets: low-fat, olive oil, peanuts plus peanut butter, peanut oil and a typical American diet with 35 percent fat. All the participants were studied for a total of 125 days--25 days on each diet--and they maintained their starting weight.

The peanut diets had relatively small amounts of peanut products but they were consumed daily, for instance, peanuts as a snack or some peanut butter on a bagel for breakfast. Those who were randomized to the peanut, peanut butter and olive oil diets all had lower total and LDL ("bad") cholesterol and triglyceride levels, yet their HDL ("good") cholesterol levels were not lowered. The participants on the low-fat diet had lower LDL levels, but also lower HDL levels and increased triglycerides. "These findings offer consumers another food option for increasing monounsaturated fats in the diet and adding variety, flexibility and eating satisfaction to diet planning," commented Penny Kris-Etherton, Ph.D., R.D., Professor of Nutrition at the Pennsylvania State University and one of the study's researchers.

The ongoing Nurses' Health Study from Harvard University also reported that peanuts may reduce the risk of heart disease, confirming previous research from Loma Linda University. Nevertheless, more research is necessary to determine if the positive effects from the peanut products go beyond beneficial fatty acids. The researchers speculated that antioxidant vitamin E, folic acid, phytochemicals, fiber, minerals and plant protein contained in peanut products may have all contributed to heart disease protection.