To Your Health

Q: What is conjugated linoleic acid? I found it on the Internet among the new cancer therapies, but I thought linoleic acid was bad if you have cancer.

A: Linoleic acid is bad if you have cancer, because it is made into a pro-inflammatory prostaglandin, one that helps cancer spread. Conjugated linoleic acid (CLA) is not made into any prostaglandin, and paradoxically is a "good" trans fatty acid. Ordinary trans fatty acids are about five times as harmful as saturated fat when it comes to increasing risk of heart disease and cancer, while CLA actually reduces the risk.

CLA is the new kid on the block among fatty acids, so we don't yet know very much except that in animal experiments it helps stabilize blood sugar, enhance immunity, and reduce artery-clogging plaques. This certainly piqued the interest of a lot of nutritionists. Research with humans looks very promising, but has only been going on for three or four years. So far, no ill effects have been observed even when CLA is supplemented at about twice the level that provides benefits.

Another paradox: The richest sources of CLA are dairy products and beef. The trend toward low-fat milk and lean meat means people get less CLA in their diets. In fact, today's typical American diet will not provide enough CLA to make much of a difference, so a supplement of about 3 grams per day is needed if you want to see some benefits. Buy a brand you trust, because some brands don't have the correct form of CLA.

Although CLA holds promise in treating cancer (especially breast and prostate cancer), it is the expectation that CLA will help with weight loss that is more likely to make it famous. CLA seems to divert calories away from fat storage and into energy production, helping dieters to lose fat rather than lean muscle. It does this by increasing the sensitivity of cells to insulin, an ability that is also very important for people with Type II diabetes.

As with the omega-3 essential fatty acids, you can expect to see eggs and possibly other foods with enhanced CLA content, making it easier to get enough CLA without taking pills. Until then, if you have a family history of cancer, diabetes, allergies, immune deficiency, heart disease, or if you want to lose weight, you will need pills for your CLA.

Q: Two weeks ago I passed a kidney stone. It easily qualifies as the most painful experience of my life. What can I do to avoid going through that again?

A: First, the obvious advice: Drink more water. However, it's not quite that simple: You must also remember to drink more water in hot weather, in dry weather, and when you sweat a lot with exercise. Pure water tastes better, so you're more likely to drink enough if you use bottled or filtered water.

About 80% of kidney stones are made of calcium oxalate, so preventing the formation of calcium oxalate is usually the second step. Your physician will analyze the stone and can tell you if it is not calcium oxalate.

Calcium oxalate is less likely to form a stone in the presence of magnesium and a citrate, so a supplement of magnesium citrate is high on the list of preventative measures. Although it can be laxative, most people can tolerate several hundred milligrams per day. Interestingly, calcium deficiency is also associated with formation of calcium oxalate stones, so you do not need to reduce dietary calcium intake as was often recommended in the past.

You may need some professional guidance to unearth the other possible contributors to your problem. The candidates are deficiencies of vitamin B-6 and glucosamine, and excessive caffeine, salt, or sugar intake.

Even if kidney stones "run in the family," chances are you need never suffer from them again. It may require only minor adjustments in your lifestyle, or you may need radical change, but most kidney stones are preventable.