Eating right in general will slow aging. Antioxidants, brightly-colored vegetables and fruits (the pigments which give them their colors are beneficial) generic vitamins and minerals - all help. Exercise helps. Keeping your weight down to normal helps. Avoiding chronic stress helps. And I am experimenting with some specific supplements just for anti-aging purposes.
Remember here that I'm not a doctor. And the state of the art in anti-aging treatments is still very fuzzy, but here goes.
Theories of Aging
Telomeres. One of the theories to explain why we age involves telomeres - the end-caps on the DNA which makes up the chromosomes in each cell of our bodies. The way I understand it, each time a cell divides, a few of these end-cap telomeres are lost. If the cell divides under bad conditions, way more of them are lost. Once the telomeres in a particular cell (or its daughter cells) are short enough, that cell can no longer divide. It may die and be replaced, or it may hang around, causing trouble. If there is no healthy cell which can divide to take its place, the cell's eventual death can lead to organ failure.
Cellular junk. Another theory involves cellular junk. If you think of a generic cell in the body as being like a raw hen's egg, the watery bulk of the cell (the egg white) is called cytoplasm. The yolk is the nucleus of the cell. And the shell is the cell's membrane. In the watery cytoplasm, proteins are made and most of the other business of the cell is conducted. If the protein manufacturing process doesn't go well, protein fragments and non-functional proteins hang around, clogging up the mechanisms. Protein can combine with sugars to produce AGE's, which cause inflammation, among other things. This happens more often if you have high blood sugar, the reason diabetics seem to age faster than most people.
Glycosylation. Excess blood sugar (or indeed, any blood sugar) can combine with proteins and fats, creating cellular junk - AGE's and AGL's. AGE's create cross-linkages in collagen, making skin and other tissues stiff and less functional. They also cause cataracts in the eye by cross-linking the proteins in the cornea.
Inflammation. Many different chronic diseases - the diseases of civilization - are brought on or aggravated by chronic low-level inflammation. Acute inflammation happens when you cut or injure yourself. The redness around the wound signals that white blood cells have gathered to fight invading germs let in through the wound. They hang around until the wound is healed, then subside. The redness goes away.
With chronic low-level inflammation, you don't see the redness, but think of it as there, hiding beneath the skin. Your body's defenses are mobilized to fight an invader which isn't there. Like a country in a long-term cold war, your body's resources are diverted to fight this enemy, and are not available for productive uses. And this misdirected energy causes problems of its own. Such seemingly unrelated diseases as lupus, diabetes, heart disease, Alzheimers and many others are caused or aggravated by chronic low-level inflammation.
One of the reasons thin people live longer than fat people is that fat itself creates inflammation. This seems to be the reason that visceral fat (fat around the organs in the gut area) is bad for you - it is inflammatory.
Free radicals. Contributing the the above mechanisms, excess free radicals cause cellular errors. Humans have a very advanced system of coping with these errors in DNA and proteins, but still, more free radicals means faster aging.
In a healthy body with lots of antioxidants, telomeres shorten slowly, so you want to stay as healthy as possible to live a long life. (Chronic stress also seems to shorten telomeres - people with a chronically ill spouse have shorter telomeres than their luckier age-mates.) It's actually possible to safely lengthen telomeres. The "safely" in the previous sentence is open to interpretation, but the herb involved, astragalus root (Astragalus Membranaceus root powder), has been in use in Chinese medicine as an immune enhancer for centuries.
Because cancer cells produce telomerase (a generic term for a chemical which lengthens telomeres), it's just a little scary to deliberately introduce telomerase into your body. So we do it carefully - about two weeks on and two weeks off. For the first 12 days of each month, we add a slightly rounded teaspoon of astragalus root powder to our diet, morning and evening. The next three days are a washout period, then the rest of the month is astragalus-free. During the first part of the month, while we're taking astragalus, we add chitosan to our supplements (it's supposed to increase astragalus absorption) It would probably be a good idea to subtract telomerase inhibitors such as green tea and fish oil. I don't know.
Support for this regimen is hard to come by, but if you're interested, start with "TA Sciences", and continue the Internet search with "astragalus" and "telomerase". Budget about a day for the search and be prepared to wade through some biochemistry.
Clearing cellular junk
One of the major components of cellular junk is badly folded proteins. When a protein is produced in the cytoplasm of the cell, it is coded as a single, long strand of amino acids. In order for the protein (I'm thinking mostly of enzymes here) to function, it must fold in a particular manner, forming what looks like a glob of protein instead of a long string. If it doesn't fold correctly, it is useless for its intended purpose and must either be stretched out again and re-folded or scavenged into its component parts so the cell can try again. If the scavenging enzymes are not quick enough, sugars can attach to parts of the protein, forming AGE's, which are harder or impossible to recycle. They become cellular junk. I'm sure there are other sources of cellular junk, but this is one which can be dealt with.
Xeronine (or xenonine - I've seen it written both ways) was first found in pineapple juice, but it's found in highest concentration in noni juice. Its method of operation seems to be in helping proteins to fold properly, thus cutting down on cellular junk. I drink one ounce of Tahiti Trader noni juice concentrate in the morning before breakfast. You want noni on an empty stomach so it will pass quickly through the stomach and into the intestines where it can be absorbed. Stomach acids are destructive. And while we're on morning juices, I mix in an ounce of pomegranate juice concentrate as well, add some water, and drink.
Carnosine is our primary glycosylation fighting supplement. It can actually remove cross-linkages from proteins after they have formed. Benfotiamine is also said to fight glycosylation.
We take carnosine supplements daily, and I also use a carnosine eye drop called Can-C which has been shown to remove cross-linking in the eye's cornea to gradually and safely heal cataracts. I used Can-C for several months, then took several years off, now I'm doing it again. I had started to get the pre-cataract "yellowing" of my corneas the first time I used it at around age 50, but the Can-C cleared it up. Last year I was actually diagnosed with early cataracts, so now I'm being more diligent. I found out recently that I had been using too little for an effective dose. I now drop about four drops per day into each eye, and I'm looking forward to amazing my eye doctor this spring, 2011.
Keeping your blood sugar in the low range of normal will also fight glycosylation, of course. This is why diabetics suffer from accelerated aging - excess blood sugar accelerates glycosylation. Keeping your weight down definitely helps to fight high blood sugar, but it takes quite a while after you lose weight before your blood sugar responds. If you have a problem with blood sugar, following a low-carbohydrate diet helps tremendously. And it helps immediately.
One of the best ways to fight inflammation is to lose fat, especially belly fat (visceral fat). Aim for the low end of the "healthy" weight range for your height, sex and age. You need some fat for cushioning, for appearance, and to produce hormones, but you don't need a lot.
Inflammation fighting supplements are fish oil, Co-Q-10 and SODzyme.
Fighting free radicals
According to Stay 40 Without Diet or Exercise, by Dr. Richard Lippman, taking truly srong free radical quenchers such as BHT, N-Acetyl Cysteine or his own patented formula, will cut the number of free radicals in your body as much as possible. His book doesn't actually say that you can stay 40 years old, but his photo on the cover is promising. NAC and BHT are fairly inexpensive.