Poorly planned veggie diet can lack nutrients
Young adults, teenagers and even children find many ways to express their individuality. Some choose to do this by making extreme dietary changes. Foods and food groups might be eliminated or added to the diet, and food choices are driven by personal feelings, philosophy and convenience.
Commonly, these changes lead to a vegetarian or primarily vegetarian diet, and meeting essential nutrient needs often is overlooked.
Question: What nutrient deficiencies are most common with an extreme vegetarian or vegan diet?
Answer: The American Dietetic Association position paper on vegetarian diets identifies several nutrients that can be inadequate in poorly planned vegetarian diets. These include protein, iron, zinc, calcium, iodine, vitamins A, D, B-2 and B-12, and omega-3 fatty acids.
Q: What are the consequences of these nutrient deficiencies?
A: Deficient intake of protein can stunt normal growth, impair immune function and affect a multitude of body functions. In particular, protein is needed for normal bone development. When both protein and calcium are low in the diet, the risk of developing early osteoporosis is greatly increased.
Iron deficiency is extremely common. Even without the extreme state of anemia, low iron status can reduce physical endurance, impair immune response, disrupt temperature regulation, affect overall energy metabolism, decrease cognitive function and lead to behavioral disturbances.
It is well known that inadequate iron intake during childhood impairs mental function and academic achievement, but it also affects young adults. In a recent study with more than 100 women age 18 to 35, normalization of iron status improved testing scores of attention, memory and learning ability by an amazing five to seven times more than women with low iron status.
Like iron deficiency, vitamin deficiencies can affect brain function and cause a multitude of other health problems. Without a source of fish oils in the diet, omega-3 fatty acid deficiency is more likely to develop over time. Although this could take years, omega-3 deficiency can impair vision and brain function.
Q: How can these nutrient deficiencies be avoided?
A: Meeting the needs for protein, calcium and vitamins A, D, B-2 and B-12 is much more likely if milk and eggs are included in the diet. Dietary iron and zinc needs are much greater for vegetarians because these minerals are poorly absorbed from most vegetable sources. To round out the needs for these minerals and other nutrients, a basic multivitamin/mineral supplement could be the answer.
Alan Titchenal, Ph.D., C.N.S. and Joannie Dobbs, 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. Dr. Dobbs also works with University Health Services.