Health and Longevity
A topic getting some traction recently in the blogosphere is the concept of caloric restriction (CR), also known as intermittent fasting (IF). The concept has been around for years because of some early research which revealed increased longevity in mosquitoes kept on a caloric restricted (i.e. low calorie) diet. I recently sat through 6 hours of lectures given by Dr. Mark Houston who presented the most recent research on this topic and the potential for health improvement by following a caloric restricted diet. Dr. Houston is a clinical professor of medicine at Vanderbilt University and Medical Director for the Hypertension and Vascular Biology Institute and the Life Extension Institute at Saint Thomas Medical Center in Nashville, Tennessee. I have sat through over 100 hours of lectures over the past year and I can tell you that there are few people that have made more of an impact on how I practice medicine than Dr. Houston.
The concept of caloric restriction in a nut shell is just as the term sounds, following a calorie restricted diet in some form or another. The protocols that have been studied included fasting for one full day per week (24 hours), cutting daily calories by 20 – 40% below normal, and cutting calories by 40% on alternating days while eating normal diet on the other days. Studies have included many different species from yeast and worms, all the way up to primates and consistently show a 15 – 66% improvement in longevity and a dramatic reduction in disease, when following such diets1,2,3,4,5. Studies have confirmed that these beneficial biological changes also occur in human studies.5,6,7,8,9,10
There are many reasons why this makes sense from a health and medical perspective. The most obvious is the fact that these diets results in weight loss and lower cholesterol, blood sugar and insulin levels, all of which reduces of the most common causes of disease and death in industrialized populations. But the reasons go deeper than this. A good analogy is wild blueberries. Wild blueberries have a higher concentration of antioxidants and other disease fighting antioxidants than those grown in controlled farming environments using pesticides. It is believed that they become hardier because they must fight harder for survival in the wild. Similar things happen in the body when then body is given less of what it needs to survive, becoming ultra efficient at using fuel and fighting off disease.
Some examples include increased growth hormone production, decreased DNA damage that can lead to cancer, marked improvement in sugar metabolism, and decreased plaque formation on blood vessels which can lead to heart attack and stroke.
Dr. Houston did recommend a more practical way to obtain the benefits of caloric restriction without consistently starving yourself. His observations have seen similar changes in his patients who exercise consistently 4 – 5 days per week for an hour, including a combination of weight training and aerobic activity, along with fasting from 6 pm to 6 am 4 days per week. I have outlined more specific protocols for some of my patients and have seen some pretty dramatic results for those who follow the program. To be clear, most people are more interested in the weight reduction aspects of these programs but this research is about extending life and reducing disease and better health. Weight reduction is just a nice side effect.
There is a supplement that has been shown to induce some of the same biological changes, including weight reduction, that I will cover in my next blog so check in next week for more information on this promising new tool that could have a dramatic impact on your health and longevity.
Until next time, stay healthy and live well… Dr. Mike
1. European J of Clinical Nutrition 2007;61:160-65
2. Science 2003;299:572
3. Proc Natl Acad Sci USA 2003;100:6216
4. Physiol Rev 2002;82:637
5. Sci Aging Knowledge Environ 2003;8 RE 2
6. Clin Nutr 2006;84:1033
7. Rejuvenation Res 2008;11:793
8. J Clin Endocrinol Metab. 2008;93:3226
9. Obesity 2006;14:1211
10. Curr Opin Lipidol 2007;18:53
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