Vegetarian diet alone is not panacea for health


POSTED: Monday, May 18, 2009

People often switch to a vegetarian or vegan diet in hope of improving their health. Often they don't realize that a solely plant-based diet does not guarantee a healthy diet. If you have aspirations to go veggie, it is important to know the potential pitfalls.

Question: What makes a diet healthy?

Answer: A healthy diet provides adequate amounts of all essential nutrients and includes foods that provide a good balance of protein, carbohydrate and fat along with a reasonable amount of dietary fiber. This requires eating balanced amounts of a wide variety of foods in moderation.

Q: Doesn't eating only “;healthy foods”; ensure an adequate supply of all essential nutrients?

A: No. There are many misperceptions about what foods are “;healthy.”; In reality, healthy foods are those that supply the nutrients the body needs. If someone is deficient in iron or zinc, then lean red meat could be considered to be “;health food”; for that person at that time. Even a diet containing only good wholesome foods needs adequate variety and balance to provide all the essential nutrients.

Q: If someone feels better after changing their diet, doesn't that prove it is good for them?

A: Not necessarily. It is common for people to make radical dietary changes in the right direction but then go too far. Initially, this dietary change brings the body into a better “;biochemical balance”; but eventually drains the body of one or more essential nutrients and leads to new and potentially serious health problems.

It can take months or even years to become deficient in some nutrients. When this happens, people have the tendency to think that they just are not following their diet carefully enough.

Q: What constitutes a healthy vegetarian diet?

A: The need for some nutrients increases with plant food diets. According to the Institute of Medicine, due to reduced mineral absorption, vegetarian diets should contain almost twice as much iron as omnivore diets and about 1.5 times as much zinc. Large amounts of wholesome plant foods can provide this, but a lower-calorie diet could lead to a deficiency.

Protein needs also increase. Many plant food proteins have lower digestibility and tend to be low in the essential amino acid lysine. Consequently, if milk and eggs are not included, it is important to eat plenty of plant foods and include ample amounts of beans and other legumes to meet lysine needs.

Meeting nutrient needs from plant foods alone requires eating significant amounts of these foods. Consequently, it is important to stay active and keep calorie needs high.


Joannie Dobbs, Ph.D., C.N.S., and Alan Titchenal, Ph.D., C.N.S., are nutritionists in the Department of Human Nutrition, Food and Animal Sciences, College of Tropical Agriculture and Human Resources, University of Hawaii-Manoa. Dobbs also works with University Health Services.