Q & A: Cholesterol and Diet
Chef Jeff's Weekly Health Tips
November 2, 1998
The following questions were posted on a professionally moderated list I am on that includes many of the top nutrition experts around the world today. The questions were then answered by
Lawrence H. Kushi, Sc.D., Division of Epidemiology, Univ of Minnesota School of Public Health and then also edited by me.
I think you will all relate to each of these questions and appreciate the accurate answers.
Q. If cholesterol can be reduced by a very restrictive diet in 3-6 weeks, why are people with a raised cholesterol level told to remain on the diet for six MONTHS?
A. Actually, people should think of dietary change as a lifelong change in habits, not just something that is prescribed for use for only a limited amount of time. If your cholesterol level is lowered in 3-6 weeks on a plant-based diet, then if you go back to what you were eating before (presumably including meat and dairy), then your cholesterol will go back up to where it was in
another 3-6 weeks.
Q. At what point will cholesterol fall to an UNHEALTHY level?
(Or stated differently, can cholesterol ever go to low?)
A. There is little evidence that drops in blood cholesterol based on dietary change can result in unhealthy levels of blood cholesterol. There is some controversy, not resolved, as to whether people with low blood cholesterol levels may be at increased risk of certain other diseases and conditions, such as stroke, suicide, and accidents. There was some thought that low cholesterol levels might increase risk of cancer, especially colon cancer, but that seems to generally have been an artifact of cancer-causing low cholesterol levels rather than the other way around. So, one of the last things I would worry about is having too low blood cholesterol levels. In any case, your body will manufacture all the cholesterol it needs for the various functions cholesterol does in your body.
Q. If it takes 30 years to build up cholesterol to the point of a heart attack, why does it only take 3-6 weeks to reduce it to a 'safe' level?
A. Because high cholesterol levels are one of many factors that ultimately leads to the development of atherosclerotic plaques (cholesterol deposits) that lead to blockage of your coronary arteries and heart attacks. It may take only a few weeks to get your cholesterol levels down to a "safer" level, but it takes much longer to reverse the atherosclerosis that is a result of
years of poor diet, lack of exercise, high blood pressure, smoking, and other factors.
Q. Can cholesterol be raised by stress and no exercise alone in an otherwise healthy person on a reasonably good diet?
Unlikely. Heart disease risk can be raised by these factors, but they operate in conjunction with raised cholesterol levels, rather than these factors acting by influencing cholesterol levels.
Q. How is it known that the suggested 'safe' level of 5.2 mmo/L (or 200mg/dl) of cholesterol in the blood is the same for everyone?
A. Every person is different, e.g. weight, height, bone structure, etc. I would not consider 5.2 mmol/l a "safe" level of cholesterol. That simply follows the AHA guidelines (5.2 mmol/l = 200 mg/dl). The guidelines don't suggest that the level is the same for everyone, but are simply that - guidelines that need to take into account other things like family history, body size, etc.
Studies of vegetarians typically place their average cholesterol levels at closer to 150 mg/dl (in some studies, even lower - 120 mg/dl or so). Studies clearly demonstrate that the higher
one's cholesterol level, the higher the risk of heart disease, and conversely, the lower the cholesterol level, the lower the risk. There is nothing particularly magical about 200 mg/dl -
heart disease risk continues to decrease as one's cholesterol level decreases. (NOTE: at the Pritikin ctr, we tell people that ideal cholesterol levels are 100 + your age, with an upper
limit of 160. The Framingham Heart Study showed that no one with a cholesterol level of 150 or below ever had a heart attack in their study. The level recommended by the AHA of 200 is just
not a healthy recommendation.)
It should be said here that an even better measure of heart disease risk would also take into account the proportion of blood cholesterol carried in low density lipoprotein (LDL) compared to high density lipoprotein (HDL) particles - the higher the LDL or lower the HDL, the higher the heart disease risk. So, some people have suggested the ratio of LDL to HDL, or the ratio of total to HDL cholesterol as a measure of heart disease risk. For example, the typical man in Framingham has a total to HDL cholesterol ratio of about 5.0, the typical woman about 4.4. The typical woman to get a heart attack in Framingham had a ratio of total to HDL cholesterol of about 4.6-6.4, while the typical man had a ratio of about 5.5-6.1. Physicians who ran in the Boston marathon had a ratio of about 3.4. People eating a macrobiotic (essentially vegetarian) diet had a ratio of about 2.8.
Q. What happens when the cholesterol is lowered to 'normal'? Does the reducing diet continue or is it relaxed?
A. As mentioned above, this should be considered a lifestyle change if you're really interested in changing the risk of heart disease. In any case, change in diet shouldn't be thought as being restrictive - the typical vegetarian eats many more different food items than the person eating a typical U.S. diet. Which is more restrictive? And also, consider the wide variety of new foods and tastes, and cooking techniques just waiting to be discovered. Think of the traditional
Mediterranean and Asian cuisines that could be explored (I'm not talking about the Olive Garden and Benihana's).
Q. How does a person who has 'normal' weight, blood pressure and no heart problems not lose weight on the cholesterol reducing diet?
A. What does "normal" weight mean? Most people in the US tend to carry more pounds than they need, and could lose a few pounds. (And as I mentioned in the weekly tip a few weeks ago, they have now lowered the recommended weights for Americans.
Q. High cholesterol is usually associated, we are told, with a high fat diet, no exercise, smoking, overweight and high blood pressure. How, therefore can a person with a moderate fat diet,
normal blood pressure, moderate exercise and 'normal' weight have high cholesterol? If they are able to burn off the fat in what they eat (because they aren't overweight - and we are
constantly told these days that eating fat makes fat) how can they have a level of high cholesterol in their blood.
A. First, it's not just the amount of fat - it's the type of fat. In particular, one should be cutting down saturated fat sources from animal foods, or simply animal fats (except maybe
from fish). You could be eating a moderate fat diet (what does that mean?) and still be consuming a diet that would result in a higher cholesterol level than if you changed your diet. Also, if you're eating any animal food (except for fish and non-fat dairy), you're probably not eating a low-fat diet.
Otherwise, assuming you've done most that is reasonable to lower the fat in your diet, there are other reasons one might have higher (or lower) cholesterol levels. There are genetic factors that control this: You place a group of people on the same diet for weeks, and there will be a wide range in cholesterol levels in the group. This doesn't mean that people with high cholesterol levels shouldn't change their diet (even on a moderate fat diet) - for most people, dietary change will result in decreases in blood cholesterol (the response to dietary change also varies from person to person, but the overall response for a group can be predicted with reasonable accuracy).
Q. It has been stated by an Australian scientist that almonds and walnuts reduce the level of cholesterol in the blood if eaten in small quantities in the day. Can this be substantiated and how does it affect the cholesterol reducing diet? Is this recognized by American and British doctors?
A. The principal studies that indicate this were conducted by US scientists, e.g., by Joan Sabate at Loma Linda University. He demonstrated that adding walnuts will decrease blood cholesterol
levels, and then he and Gary Fraser demonstrated that Seventh day Adventists who consumed nuts regularly had a decreased risk of heart disease. We demonstrated that same thing in a study of women in Iowa, and this has been replicated in a study of Nurses that is being conducted out of Harvard University. Nuts probably are a good source of polyunsaturated fats that tend to lower cholesterol levels. They also tend to be a good source of vitamin E, which helps protect LDL from oxidation (which increases their atherogenicity). (NOTE: Nuts are very high in calories and calorie density, so for those of you who are trying to "get well", use these foods with extreme caution and moderation if at all).
Q. Why is coconut a very big 'no-no'? It doesn't contain any animal fat and the Pacific Island peoples seem to thrive on it?
A. Again, it's the type of fat. Coconut is about 95 percent saturated fat, which raise blood cholesterol levels (most animal fats are about 40-50 percent saturated, vegetable oils, perhaps
10-15 percent). It's also particularly high in palmitic acid, a saturated fat that is among the worst in terms of raising cholesterol levels. Pacific Islanders typically also were very active physically, among other major lifestyle differences.
Q. The cholesterol reducing diet states - only eat two whole eggs a week. I read a few years ago that the thinking on the badness of eating eggs had been refuted. What is the score on this?
A. Eggs do make a difference. It would be even better to eat no eggs. It is only in relation to saturated fat that it's not so bad.
Q. Are there any up-dated views on this condition? Most ideas have not changed for 15 years and medical science is always moving forward and finding new things out. E.g. it has only recently been found that blood does not flow through veins and arteries as believed, but swirls, which alters the way heart valve surgery is now carried out.
A. Dietary advice has been modified and continues to be. The best bet would be to eat a whole grain, fresh vegetables and fruits-based vegetarian diet, no animal foods except maybe fish
on a semi-regular basis. Include nuts, seeds, soy and other legumes (NOTE: In limited amounts)
Q. It has been known in America for some time that vegetable oil and hydrogenated vegetable oil (margarine) is a cause of furred up arteries. I also heard that they also believe that these are a factor in stomach cancer? Why then are they both used so widely in food manufacture, when it is known they are both very bad for health?
A. What does "furred up" arteries mean? Vegetable oils per se aren't bad - it's only when they are hydrogenated. They are used widely because they are inexpensive and the hydrogenation
process results in longer shelf life (hydrogenation results in less likelihood of oxidation and rancidity). (NOTE: Vegetable oils are also extremely high in calories and the most calorie dense of any food. Therefore, it is important to keep their use to a bare minimum also, if they are used at all.)
Q. Why has butter got such a bad name when you can't find it in processed manufactured food anymore (it’s all vegetable oil or margarine), and most people use margarine of some sort instead of butter for spreading/cooking because they think it to be more healthy (because we are constantly told so) and yet there are more overweight people than ever before and also a big increase in heart disease?
A. Butter isn't necessarily better than margarine for cholesterol and heart disease. The dramatic increase in overweight is probably attributable in part to people substituting refined carbohydrate foods for fat in the diet, and also, less physical activity, not so much replacing margarine for butter. (NOTE: Neither butter nor margarine is recommended for those trying to regain their health or stay healthy. The best choice would be to use a little all fruit jam or jelly.)
I hope you find these Q & As helpful.
Please forward any of your own personal questions and I will see that they get answered immediately.
And so, for this week’s health tip....
remember what Larry stated above......
The best bet would be to eat a whole grain, fresh vegetables and fruits-based vegetarian diet, no animal foods except maybe fish on a semi-regular basis. Include nuts, seeds, soy and other legumes (NOTE: Use nuts and seeds in limited amounts)
Have another great week, and remember...
Your Health Is Your Greatest Wealth!