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Recently, a friend who has been trying to lose weight for many years indicated that her new diet requires that she eat only meat. When I asked whether she was also eating fruits she answered that fruits are full of sugar, thus not part of her new healthy diet. This is a common recommendation for many of the new popular diets - avoid carbohydrates in any form. There are some good arguments to be made about avoiding sugar, but if this approach takes fruits out of your diet then you may be missing important nutrients that might make you healthier in the long term. I want to introduce you to one of these nutrients: ursolic acid.
I was recently honored by an invitation to give a TED talk on this topic area. The video is available here. http://www.youtube.com/watch?v=4SvkaK2Al0o&feature=plcp
As the title of this blog suggests ursolic acid is found in apple (mostly in the skin), cranberries and prunes, as well as in elder flower, basil, bilberries, peppermint, rosemary, thyme and oregano. Although a considerable number of studies have already documented the ability of this chemical to inhibit the growth of various types of cancer cells, that's not why I want to mention it. Eating fruits and spices that contain ursolic acid might also enhance brain function and reverse some of the negative effects of obesity upon the brain as you get older.
Obesity is fast becoming one of our most serious threats to human health. Obesity contributes to the development of many chronic diseases including type 2 diabetes, hypertension, cardiovascular diseases and cancer. Obesity can directly damage the liver, muscle and kidneys. Obesity also affects how your brain functions. Obesity often leads to diabetes; individuals with diabetes have a higher risk of developing mild cognitive impairments and Alzheimer's disease as they age. Similar to what happens in the body, your brain can also develop a form of insulin resistance, which leads to impaired signaling by your neurons and deficits in cognitive function. The underlying mechanisms are due to inflammation forming in the brain in response to having too many fat cells in your body. The obesity-induced cognitive impairment is now understood to be directly caused by the development of chronic brain inflammation and insulin resistance. Essentially, obesity is an accelerated form of fat tissue aging and obesity predisposes us to diseases that are common in old age.
This is where apples, cranberries and prunes might come to the rescue. Studies have shown that ursolic acid can improve cognitive functioning by increasing your brain and body's sensitivity to insulin. The biological mechanisms have now been fairly well investigated and it appears as though ursolic acid is able to correct the errors in metabolism induced by the presence of long term obesity. The real challenge is to discover how many apples, prunes and cranberries are necessary to eat in order to achieve these benefits. Studies on humans have never been performed.
Will you lose weight by eating these fruits? Maybe, it depends upon what else you're eating. Will you lose weight avoiding fruits and berries while only eating meat? Yes. However, over the long term it is likely very unwise to do so. However, the benefits of an all meat diet are more immediate as compared to the benefits of eating apples, cranberries and prunes, because their effects upon your health take longer to notice. Essentially, these fad diets have not been around long enough for medical science to determine the long term risks. Caloric restriction is the only valid, scientifically proven dietary intervention that has been shown to slow the aging process and improve health. The reason we hear so little about this approach is because no one stands to make a profit on all of us eating less food and more apples, cranberries and prunes.
© Gary L. Wenk, Ph.D., author of Your Brain on Food (Oxford, 2010)
