Why does dietary diversity matter? Because different foods may affect different problems. Cabbage, cauliflower, broccoli, and Brussels sprouts are associated with lower risk of colon cancer in the middle and right side of our body, whereas risk of colon cancer further down on the left side of our body appears to be lowered by carrots, pumpkins, and apples. So, different fruits and vegetables may confer different risks for cancer of different parts of even the same organ.
Variety is the spice of life and may prolong it. Independent of quantity, variety in fruit and vegetable consumption may decrease lung cancer risk, meaning if two people eat the same number of fruits and vegetables, the one eating a greater variety of them may be at lower risk.
And it’s not just cancer. In a study of thousands of men and women, a greater quantity of vegetables and a greater variety may independently be beneficial for reducing the risk of type II diabetes. Even after removing the effects of quantity, each different additional two items per week increase in variety of fruit and vegetable intake was associated with an 8% reduction in the incidence of diabetes. Why? Well, it may be attributable to individual or combined effects of the many different bioactive compounds contained in fruits and vegetables; thus, consuming a wide variety will increase the likelihood of consuming more of them.
All the vegetables may offer protection against chronic diseases, but each vegetable group contains a unique combination and amount of these phytonutrients, which distinguishes them from other groups and vegetables within their own group. Because each vegetable contains a unique combination, a great diversity of vegetables should be eaten to get all the health benefits.
Does it matter, though, if we get alpha-carotene or beta-carotene—isn’t an antioxidant an antioxidant? No, it’s been shown that phytochemicals bind to specific receptors and proteins in our bodies. For example, there’s a green tea receptor in our body, a receptor for EGCG, a key component of green tea. There are binding proteins for the phytonutrients in grapes, onions, and capers. I’ve talked about the broccoli receptor already. Recently, a cell surface receptor was identified for a nutrient concentrated in apple peels, and importantly these target proteins are considered indispensable for these plants foods to do what they do, but they can only do it if we eat them.
Just like it’s better to eat a whole orange than just take a vitamin C pill, because otherwise, we’d miss out on all the other wonderful things in oranges that aren’t in the pill, by also eating a different fruit, like an apple, we won’t miss out on all the wonderful things in apples that aren’t in the orange. When it comes to the unique phytonutrient profile of each fruit and vegetable, it’s like comparing apples to oranges.
Featured photo source: Isagenix
About Michael Greger M.D.Michael Greger, M.D., is a physician, author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous “meat defamation” trial. Currently Dr. Greger proudly serves as the Director of Public Health and Animal Agriculture at the Humane Society of the United States.