Sticking to a Heart Healthy Diet with David Katz, MD
Confused about everything from healthy food to hypertension? Then read on!
WebMD Weight Loss Clinic - Live Events Transcript
Reviewed By Kathleen Zelman, MPH, RD, LD
What's for dinner? Good question. If you're confused about the low-fat claims on food labels, the safety of today's popular diets, or the effects of certain foods on your health, from hypertension to heart disease, read what David Katz, MD, author of The Way to Eat: A Six-Step Path to Lifelong Weight Control, had to say on WebMD Live.
The opinions expressed herein are the guest's alone and have not been reviewed by a WebMD physician. If you have questions about your health, you should consult your personal physician. This event is meant for informational purposes only.
Moderator: Welcome, Dr. Katz. Can you give us some guiding principles about eating for heart health?
Katz: I certainly can. Good news is that eating for heart health is the same as eating for overall health. Not all that long ago there was consideration of many different diets for different medical conditions. But, of course, the same individual who is at risk for heart disease also is concerned with weight control, perhaps a risk for diabetes and overall health. The basic principles of a heart-healthy diet are the principles of a health-promoting diet. Namely the diet should be:
The overall fat content of the diet need not be severely restricted, provided the fat sources are the right ones. Ultimately, the only way a diet can promote lifelong health is if it's a diet you can stick with for a lifetime. A heart-healthy diet is not a diet to get on and get off, but a way of life.
Member: I know of a small study where they compared a high avocado diet with the AHA cardiac diet. They both lowered the cholesterol total, but the HDL did not drop with the avocado diet. What are your thoughts on "the good fats"?
Katz: I believe that fat in the diet is important to heart health in terms of quantity and quality. The typical American diet is slightly excessive in total fat. But more importantly, it derives far too much of its fat from saturated and trans fatty acids. Avocado is one of only two fruits high in fat. The other is the olive. Both of these fruits are rich in health-promoting monounsaturated fat. There is evidence from clinical trials that a Mediterranean diet rich in monounsaturated fat can significantly lower the risk of heart attack in individuals with established heart disease. There is evidence as well that fat restriction can lower the risk of heart attack.
Anthropologists tell us that our ancestral intake of fat was approximately 25% of total calories, and that almost all of the fat they ate was mono- or polyunsaturated. Further, the meat consumed by our ancestors was an excellent source of health-promoting omega-3 fatty acids. In my view, if one combines the best of modern science with insights about ancestral dietary pattern, it points to a diet that provides maximal cardiac benefit. Such a diet helps to lower cholesterol while maintaining high levels of HDL.
While the American Heart Association Diets do represent an improvement over prevailing dietary habits in the U.S., we are definitely learning that we can do even better. So enjoy those avocados. Just exercise portion control because they are high in calories.
Member: What is the better source of omega-3 oils: Walnuts or fish? Any other non-animal sources?
Katz: Yes. The single best plant source of omega-3 fatty acids is flax seed. Flax seed also has the benefit of being rich in fiber and lignans, which are phytoestrogens and possibly cardio-protective. However, all plant sources of omega-3's provide alpha linolenic acid. The health benefits of omega-3's are particularly associated with docosahexanoic acid and eicosapentanoic acid. These long-chain omega-3's are found in fish and marine animals. We can manufacture them from alphalinolenic acid, but do so with variable and often limited efficiency. Thus, for people willing to consume animal products, the best evidence supports the use of fish oil for cardiac benefit. The recommended dose for prevention of heart disease is one gram twice daily.
For strict vegetarians one tablespoon of flax seed oil or one tablespoon of ground flax seed daily is the best substitute. Walnuts do contain omega-3's in lower doses but also provide fiber, other nutrients, and mono-unsaturated fat. They certainly are a heart-healthy food.