DEAR DR. BLONZ: I'm taking a dietary supplement that contains OPCs along with vitamins, minerals and herbs in an isotonic form. It is purportedly a more efficient delivery system, as it goes through the stomach and right to the small intestine, allowing for close to 95 percent absorption (since it's not diluted by stomach acid). Also, this speeds up the nutrients' entry into the circulatory system, occurring within five to 15 minutes, as opposed to the average four hours that a typical pill or capsule takes. What are your thoughts on this? -- G.C. San Diego

DEAR G.C.: Wow! Your descriptive statements certainly provide a supplement of puffery. They seem to be taken directly from promotional product literature. It is unclear whether there is any substantiation for these claims, or what extra benefits you stand to gain by taking such a product.

Ninety-five percent absorption for all nutrients? That's doubtful. The degree to which a nutrient is absorbed depends on the individual nutrient and a number of additional factors, including whether there is a deficiency (or an excess) of it in the body and in the diet. With many nutrients, only a small fraction gets absorbed even under the best of conditions.

You say your supplement's delivery system is "purportedly more efficient," but I would be interested to see any evidence supporting this claim. Pills, capsules or powders work just fine. As a rule, it's usually best to take vitamin and mineral supplements at mealtime. Digestion and absorption are designed to get the good stuff out of our foods by keeping the mass of food churning and in contact with the absorptive surfaces for an extended period of time.

For those interested, OPC is an abbreviation for "oligomeric proanthocyanidins." These are naturally occurring bioflavonoids found in grape seeds and skin, pine bark extract and other plants. They have been shown to perform as effective antioxidants and are currently being investigated for their role in protecting against chronic disease. But no one antioxidant can carry the entire load.

As with other lessons from nature, always consider the context in which the substance occurs. A whole food may contain a superstar nutrient with particular biochemical abilities, but it also contains a symphony of healthful components perfected over time to work together with that star. It is of questionable value to rely on a supplement without also having a healthful overall diet and lifestyle.

DEAR DR. BLONZ: I read with interest your article on the "milk effect" of putting tea in milk. It triggered this question of mine: Does adding half-and-half or milk to coffee also blunt coffee's antioxidant prowess? -- J.H.

DEAR J.H.: Great question. The phytochemicals in the coffee bean are a different family of compounds. They come from the bean (seed) portion, not the leaf, as with tea. They are not affected the same way.

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.

DEAR DR. BLONZ: I read that the best calcium supplements are made from bone. I have also heard that milk is not the best source of calcium because of the protein binding. What are your thoughts? -- R.T., Richmond, California

DEAR R.T.: Calcium hydroxyapatite is the key calcium compound found in bones. Because it is bone, it contains all the minerals found in bone, and somewhere along the line, someone came up with the idea that it would be an ideal calcium supplement. But calcium has to be absorbed before it can be utilized, and hydroxyapatite has yet to demonstrate its superiority as a calcium supplement.

Calcium carbonate is the most common form of calcium found in supplements, but if higher absorption is the key, the best bets are calcium citrate malate or calcium citrate.

The bottom line regarding calcium? It is more important to get calcium into your system than to spend time worrying over which form might have a few percentage points' greater absorption in a particular study. And regardless of which form you end up taking, it is widely accepted that the best time to take calcium is at mealtime.

You also bring up the issues of milk and "protein binding." Explaining the idea of protein binding in relation to calcium is a bit more complicated, so bear with me as I walk you through it. First, milk should not be the focus here. The primary issue is that when we consume more protein than the body needs, the excess does not get stored. Rather, excess protein gets directed to other uses. The bulk of protein's amino acids building blocks are converted into energy (fat), something we all know the body is quite efficient at storing.

Changing protein's amino acids into energy creates some metabolic refuse, and this must be eliminated from the body through the kidneys. Compounds being disposed of by the kidneys often grab "escorts" in order to leave the body through the urine. The refuse from the conversion of protein into energy tends to have a negative charge, and the kidneys must buffer this with something that has a positive charge; calcium can serve this purpose.

Calcium is not the first or only choice. In fact, there will be many other "positive" buffering compounds in any balanced diet that contains healthful amounts of fruits and vegetables. If, however, little else is around, calcium can get the call. When calcium leaves the body in this way, more calcium can be pulled from the bones to maintain the required level of calcium in the blood.

The bottom line is that some calcium can be lost when one eats a high-protein diet, but mainly when the diet does not contain the recommended intake of fruits and vegetables. The people who overdo it with protein, unfortunately, are often the ones who do not have a well-balanced diet.

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.

DEAR DR. BLONZ: At the start of the new year, I made a commitment to lose weight. I have been down this frustrating road many times in the past, but the recent passing of a friend has provided new motivation. I have used a low-carb diet with some success, but my weight loss eventually slows down to a crawl. While eating almost nothing (compared to my usual diet), my weight becomes stable, and this drives me up the wall. I am hoping for some guidance. -- F.S., Oakland, California

DEAR F.S.: Continued frustration with weight loss often comes from a misunderstanding of exactly what happens when the body fails to receive the calories needed to maintain its weight. Pounds can drop quickly when people go on fasts, opt for drastic low-carbohydrate diets, or use regimens that include diuretic herbs. Excess body fat can be lost, but some of the loss can be water weight: a type that is quickly regained when the program ends. There can also be risks with these plans.

When you go on a diet, you create a situation in which insufficient calories are consumed to satisfy the body's demand. Because the body operates on a balanced energy "budget," it needs to borrow needed energy from its "bank account" -- stored body fat. In tandem with this, the body goes on a bit of a work slowdown, letting you know that it is not pleased. You know why you are consuming less food, but your body's survival systems are not in the loop. During weight-loss diets, the body becomes a raving miser, cutting out all unnecessary uses of energy to weather what it assumes is an ongoing famine.

The net effect of all this is a reduction of our basal metabolic rate (BMR), the energy used while the body is at rest. The reduction brings about a lowering of body temperature. A dieter may notice a greater tendency toward chills and fatigue, and perhaps a need for additional sleep. These are all normal adaptations as you deprive your system of the energy it needs and expects. But perhaps the main impact of a reduced BMR is that the number of calories needed every day drops, slowing the rate of weight loss.

Exercise can become an ally to reverse this trend. When you achieve and maintain a moderate activity level during a weight-loss program, your BMR will not drop as dramatically. As the level of exercise increases, you not only reduce the drop in BMR, you burn more stored fat. Exercise has even been shown to reduce the nagging hunger that often plagues the dieter.

Statistics show that a minority of Americans keep active on a regular basis. Clearly, though, for those who embark on a weight-loss plan, exercise can be the missing link to staying on track.

A consult with your physician is always an important first step, especially if there are ongoing health problems or risk factors involved with increased activity or dietary changes. Also, having a guidebook can help with inevitable bumps in the road. I recommend "A Small Guide to Losing Big" by registered dietitian Cheryl Forberg. This book covers many aspects of weight loss, from the perspective of a nutritionist who has worked on "The Biggest Loser" television show.

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.