Q & A: When Does Aging Begin? Puberty May Hold The Key


Q & A: When Does Aging Begin? Puberty May Hold The Key

While nobody knows for sure what triggers aging, it may stem from a sequential turningon of genes, a process that begins at about the age of 12. Or it may simply be the final process in the development of an organism.

Q: At what point in life does aging begin?

A: It's not clear when aging begins because we don't yet understand what aging is or what causes it. Most people think of aging as something that begins when we start to slow down, or when overt signs of deterioration, such as balding or wrinkles, begin to appear.

If you look at world-class athletes who have to be at a peak-performance level to compete successfully, their skills generally begin to erode around the age of 30. Some athletes go downhill sooner. Female swimmers and gymnasts are often "over the hill" at 20, but this may be because they can perform better in a physically immature state rather than because they have aged. A female gymnast, for example, cannot perform as well on the 4-inch balance beam when her breasts and hips have developed fully. On the other hand, most athletes benefit from the added weight and strength they develop in their 20s, until the effects of aging set in their 30s.

Baldness sometimes begins in men in their late teens, but that is usually because of a condition called male pattern baldness, generally considered a disease rather than attributable to aging. Most people begin to show overt signs of skin wrinkling in their late 20s, but some people appear to be virtually wrinkle-free until their 40s.

Another way of looking at aging is as the final process in the development of an organism. According to this view, growth, differentiation, puberty, physical maturation, menopause and aging all are part of a developmental program that begins at conception and ends in death. The vast differences in lifespan among mammals suggest such a program, as does the fact that all the genes for each species are contained in every nucleated cell of every individual (which makes cloning possible). This view suggests that the program is embedded within the genome, or the organism as a whole, and that specific genes are turned on or off as the program unfolds.

Food restriction, the only method shown to extend maximum lifespan and reverse many of the signs of aging in rodents (it is now being looked at in monkeys and humans), provides evidence for the developmental theory of aging. When laboratory rats or mice are severely food-restricted very early in life (right after weaning), they remain small, juvenile, and fail to mature sexually. They also suffer seizures and other severe side effects, in some cases leading to death. The survivors of this highly stringent regime, however, are later (after being put on a normal diet) capable of giving birth to normal offspring at greatly advanced ages, and some of them go on to live extremely long Lifespans...as much as double their normal maximum lifespan!

If the developmental theory is true, then it can be said that aging begins when the first genes associated with aging are turned on and become active. No one has yet pinpointed the genes involved in aging, although companies such as Geron, MRX Biosciences, GeriGene and Lifespan Biosciences are actively looking for them. It may be that there is a sequential process involved in aging, whereby one set of genes or another are turned on as the clock ticks, eventually leading to senescence and death.

It may be that the initial aging genes are turned on at puberty. Food-restriction experiments, which clearly interfere with puberty, suggest this, as does the fact that developing into an adult is the first step in growing old and dying. The fact that the thymus (the master gland of immunity) begins to atrophy during our teen years is further evidence that aging may be kicking in.

Another piece of evidence that puberty may be the beginning of the end is the fact that the age at which we are statistically least likely to die is 12, just before puberty usually sets in. After the mortality associated with the neonatal period is over, our chances of dying are reduced every year until we hit our peak at age 12. Thereafter, we experience a slow descent, in which our chances of dying increase with every passing year.

The one thing that can be said, almost universally, about being 12 is that at that age we want to grow older. Hardly anyone wants to be 12 again. What we're after is to be strong, mature adults, without having to pay the price of aging and death.

Q: On several occasions, you've written that supplemental conjugated linoleic acid (CLA) can help reduce body fat. Other than a photograph showing a CLA rat with less body fat than a normal rat, you've presented no evidence to support this. Is there any published evidence that CLA can reduce body fat?

A: There have been many anecdotal reports from bodybuilders that supplemental CLA is, perhaps, the most effective nutritional way of reducing body fat and building muscle, but no published studies in the scientific literature has validated this finding. The main published evidence to date is in U.S. Patent number 5,554,646, which was granted on Sept. 10, 1996, to the Wisconsin Alumni Research Foundation (WARF) in Madison, Wisc.

The photograph you refer to, which graphically portrays the reduction in body fat in a rat fed with CLA, was taken by researchers at WARF during the research studies they performed to obtain their patent. One study cited in the patent involved feeding eight pigs a control diet containing 0.5 percent corn oil, while eight other pigs received the same diet with 0.5 percent CLA instead of corn oil. The experiment was continued until the pigs grew from 5 kilograms (kg), or about 11 pounds of body weight, to 13 kg. After autopsy, it was found that the pigs fed CLA had significantly less body fat than the control animals.

In another study, 32 mice were fed 0.5 percent CLA or corn oil mixed into a standard diet. As with the pigs, the results showed that the CLA mice had significantly less body fat than the control mice. Despite this, there was no overall difference in body weight between the two groups. This occurred because there was more muscle tissue in the CLA rats than in the controls.

The patent also cites evidence that CLA reduced body fat in human subjects 20 to 45 years old who were about 10-percent overweight. After their body composition was estimated by hydrostatic weighing (submersion in water), the subjects were given 0.1 to 10 grams a day of CLA in their diet. After four to 10 weeks, the subjects were found to have significantly less body fat than before, without any other change in their diet.

Q: I've read frequently in your publication and others that dietary iron generates toxic free radicals that can contribute to cancer, arthritis and other diseases. Yet, most of the multi-nutrient products I see continue to have iron as an ingredient. Why is this so?Are these companies oblivious to the evidence, or is there some other reason?

A: One reason some companies continue to include iron in their nutrient formulas is just laziness. Once they put a formula together, they never change it. Life Extension Mix, on the other hand, has been changed numerous times to reflect the latest evidence about the benefits of various nutrients.

Another reason is that some companies don't follow the scientific literature. They keep their formulas intact simply because they're not aware of the studies showing that excessive iron can be dangerous.

A third reason is that there are many women and children in the United States who suffer from iron-deficiency anemia, and evidence for this deficiency continues to be published as often as evidence for the dangers of iron. For example, the March 26, 1997, issue of The Journal of The American Medical Association (JAMA) carries a report from a multi-center study, the aim of which was to determine the prevalence of iron deficiency and iron-deficiency anemia in the U.S. population. Iron deficiency was defined as showing an abnormal value for at least two of three laboratory tests of iron status, and iron-deficiency anemia as iron deficiency plus abnormally low hemoglobin.

The study population included 24,894 males and non-pregnant females, aged one year and older, examined in the third National Health and Nutrition Examination Survey from 1988 to 1994. It was found that 9 percent of children 1 to 2 years old, and 9-11 percent of adolescent girls and women of child-bearing years, were iron deficient. Anemia was found in 3 percent of the first group and 2-5 percent of the second group. When extrapolated to the general population, these figures correspond to 700,000 small children and 7.8 million women with iron deficiency in the United States.

So, iron deficiency is a real problem among a significant number of younger women. However, most men and me vast majority of women are not deficient in iron. The solution to iron deficiency in a minority of women is not to risk iron poisoning in the majority of Americans by including iron in products such as multi-nutrient formulas and popular breakfast cereals that are consumed by millions of people.

Iron should be taken by those who need it and only those who need it. It can be taken in their diets or from dietary supplements specially designed to meet their needs. It would also help if papers in heavily-quoted medical journals such as JAMA would discuss the risks of dietary iron when discussing the problem of iron deficiency. It would help as well if more health care professionals knew about the growing body of evidence regarding the risks of excess body stores or iron.

Q: I've been hearing a great deal about polyphenol antioxidants lately. What's so special about polyphenols? How are they different from other antioxidants?

A: There are many different types of antioxidants. Some antioxidants, such as beta-carotene, lycopene and other carotenoids are highly effective against singlet oxygen radicals; others such as vitamin E and selenium are effective against peroxyl radicals formed in lipid-rich areas such as membranes.

Polyphenol antioxidants, which are found in red wine, grape juice, tea (especially green tea) and chocolate are particularly effective in countering the oxidation of cholesterol-rich, low-density lipoproteins (LDLs) in the blood. Recent studies have shown that oxidized LDL plays a critical role in the buildup of artery-clogging plaque, which accumulates at sites in the interior arterial walls that have been injured by chemicals such as homocysteine.

In the November 1996 issue of the Journal Of Agricultural And Food Chemistry, Joe A. Vinson and colleagues at the University of Scranton in Pennsylvania studied 39 food-derived antioxidants representing eight classes of chemicals. The antioxidants, ranging from vitamins and flavones to anthocyanins, were studied for their ability to inhibit LDL oxidation in test tubes. They found that polyphenols from tea were the most potent inhibitors of LDL oxidation. One tea compound, in fact, was 20 times better than vitamin C, the most potent antioxidant.

Q: I'd like to take fish oils because of the benefits I've heard they provide, but my doctor told me not to because they raise levels of LDL cholesterol, the bad form of cholesterol. Is this true? If so, should I avoid taking them?

A: While it's true that fish oils can raise LDL levels, they also lower the chances of getting breast cancer, heart attacks and autoimmune disease, and are among the few substances capable of lowering triglyceride levels, which increase the risk of cardiovascular disease. So, the risk that may be posed by elevated LDL levels is more than counteracted by the multiple health benefits of fish oils.

Recently, scientists at the University of Guelph in Ontario discovered a way to block the one detrimental effect of fish oils, namely its ability to raise LDL levels. They randomly assigned a dozen men each to three daily regimens: 900 mg of garlic (in three sugar-coated pills); 12 grams of fish oil (in 1 gram capsules); or a combination of the two. A fourth control group received garlic-free sugar pills and capsules of vegetable oil.

As reported in the February 1997 issue of the American Journal Of Clinical Nutrition, LDL cholesterol dropped by about 14 percent in the garlic-only group. Fish oil alone lowered triglycerides by 37 percent, and raised LDL cholesterol by 8.5 percent. However, the men who received both fish oils and garlic showed reductions in both triglyceride levels (34 percent) and LDL cholesterol (9.5 percent).

The results are clear-cut: Anyone taking fish oils should also take supplemental garlic.

Life Extension Foundation.

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