Calorie restriction, mimetics and you

Calorie restriction

Calorie restriction, otherwise known as CR, is the practice of consistently reducing the amount of food you eat while still maintaining proper nutrition. It is used by some people in the hopes of delaying and reducing the effects of age-related disease, in the ultimate hope of living longer. Does it work? In animals other than humans, such as rodents, dogs and monkeys, the answer is yes. In humans, we just don’t know yet. There are some indications that CR could shorten your life just as easily at it could extend it.

The are several positive effects of calorie restriction in non-human studies, including delayed onset and severity of diabetes, heart disease and cancer, as well as Parkinson’s, Alzheimer’s and Huntington’s diseases. There tends to be a decrease in tumor growth, in chronic disease, and in oxidative damage to cells. Generally, immune response, memory, energy and stress resistance are also improved. Telomere (the “end cap” of your DNA) maintenance in some cell types is improved as well. And last but not least, it can extend lifespan, up to 50% or longer in rodents.

There is some evidence to suggest that CR will benefit humans:

- results in primate studies suggest the effect of calorie restriction is similar to that of rodents

- a community of people called the Calorie Restriction Society, who have been practicing self-imposed calorie restriction for a number of years, claim numerous health benefits like improved immunity and energy

- incidence of diseases like diabetes and cardiovascular disease can be correlated with calorie intake

The widespread practice of calorie restriction, however, is simply not realistic. Clearly, people like to eat. Food tastes good. It is difficult to imagine having a quality lifestyle if you are constantly thinking about food and the number of calories you consume, but are always hungry. There are other potential negative effects of calorie restriction as well:

- less effective when started later in life (based on rodent studies)

- potential menstrual irregularities and hormonal changes

- reduced bone density

- loss of muscle mass

- loss of energy

- looking older than you actually are

- nutrient deficiency

- feeling cold all the time

- loss of libido

I guess the question is, are you willing to put up with all those potential negative effects to live possibly ten, twenty, or thirty years longer? Before you answer though, you need to be more informed. Calorie restriction doesn’t work for everyone the same way. Scientists have discovered that your response to CR may be determined by your genetic makeup. In other words, it is possible that in the process of trying to live longer, you may actually shorten your life. At this point, it is not possible to predict what effect calorie restriction will have on any particular person.

Calorie restriction mimetics

CR mimetics are supplements that you could take that would potentially provide some or all of the benefits of CR without the reduction in calories. Several drugs have been considered as CR mimetics, though none of them have sufficient scientific data to support taking at this time. Not for the purpose of living longer anyway.

- 2-deoxy glucose (2DG) is a glucose analog that your body cannot metabolize. Even worse, 2DG blocks glucose uptake which is an essential component of metabolism. Although it is being considered for use with epilepsy, it is toxic to people. Do not take this unless directed by your doctor.

- Metformin is the most effective drug used in the treatment of Type 2 diabetes. It also helps reduce LDL cholesterol and may have other positive effects on insulin-sensitive diseases. There are many potentially negative side effects, though they are relatively mild. There is no clear evidence to suggest that this will reduce aging, even in lab animals. You should not be taking this unless prescribed by your doctor.

- Resveratrol, as recommended by both Barbara Walters and Dr. Oz, is by far the most popular purported CR mimetic in the media, despite a severe lack of evidence that it actually increases life span in mammals. There is pretty good evidence that resveratrol can protect laboratory mice from toxicity associated with a high fat diet and some very preliminary indications that it may be useful at helping type II diabetics control their blood glucose levels. Despite generally being considered safe, there are also some concerns about side effects associated with resveratrol. Derived from red grapes, blueberries and peanuts, this drug can influence the way in which prescription drugs are metabolized. Considering that 90% of Americans aged 60 and over are taking one form or another of prescription drugs, this is not a good feature to have in a CR mimetic. Resveratrol is available without a prescription, but the quality and concentration of resveratrol in these supplements varies significantly. Much additional study is needed before it will be clear whether or not resveratrol has any beneficial health properties for people.

- Rapamycin is likely the most promising anti-aging drug to date, having extended lifespan in a variety of organisms including yeast, nematodes, fruit flies, and mice. It is currently used clinically as an anti-cancer agent and to suppress the immune system in organ transplants. It is not available for purchase by the general public. More recent studies in lab animals have suggested that this drug may be beneficial for Alzheimer’s and Parkinson’s disease and may even improve learning and memory. Watch for this one in the near future.

That’s it, that’s the list. In summary, there are not yet any CR mimetics that are effective, safe and commercially available. That’s the bad news. The good news is that there probably will be within your lifetime. In the meantime, there is something you can do to live longer, and still maintain the quality of your life.

If you are overweight, consuming 10-20% fewer calories will, without a doubt, lower your blood pressure and cholesterol, improve insulin response, reduce body fat and help you to obtain a more optimal weight. All of these can easily lead to a longer lifespan.

Regardless of your weight, you can exercise regularly, eat healthy and become an active, involved member of the community you live in. Enjoy life, live it completely and you will almost certainly add many healthy years to your life.