DEAR DR. BLONZ: I'm taking several vitamin and mineral supplements and OPCs in what is referred to as an "isotonic form." This form is supposed to be a more efficient delivery system as it goes through the stomach and right to the small intestine, thereby allowing close to 95 percent absorption due to not being diluted by stomach acids. Also, it's said to speed up entry into the circulatory system, occurring within 15 minutes as opposed to four hours or more for a regular pill or capsule. What are your thoughts on taking vitamins and minerals in this form as opposed to a regular pill or tablet? -- C.G., Sun City, Ariz.

DEAR C.G.: "OPC" refers to the tongue-twisting term "oligomeric proanthocyanidins." It's no wonder they stick with the letters. OPCs are naturally occurring bioflavonoids that are found in grape seeds and skins, pine bark extract and other plants. They function as antioxidants, meaning that they attract and combine with reactive oxygen species before they can cause damage. OPCs are being investigated for a potential role in protecting against chronic disease, but keep in mind that supplements cannot replace whole foods and what they have have to offer. With supplements you may get a few standouts, but using a sports analogy, it would be like having a star player without a coach or the rest of the team.

As far as "isotonic" goes, it is questionable who benefits besides the company making the sale. Isotonic means "the same tone," but in physiological solutions, it usually refers to a concentration of ingredients similar to those inside of a cell. The idea of an isotonic liquid is that it will not pull fluids from inside the cell and this may facilitate bioavailability. When they give IV solutions, for example, they usually give them in isotonic saline because they don't want to affect blood pressure or volume or the health of the cells. With dietary supplements, the question one might ask is: What difference does it make if the substance is absorbed slightly faster?

In terms of your product, a 95 percent absorption rate is bogus as a general claim. The rate of nutrient absorption depends on a number of factors, such as the nature of the nutrient; whether the subject already had a deficiency, sufficiency or excess of the nutrient; and other substances present in the digestive system at the same time.

You say it is described as "a more efficient delivery system," but I would be interested in seeing any evidence to support such a claim. Pills, capsules, powders or liquids work just fine -- isotonic forms of dietary supplements have not been shown to be more effective. As a rule, it's usually best to take vitamin and mineral supplements at mealtime. Digestion and absorption are designed to liberate the nutrients from the foods by keeping the food churning and in contact with the absorptive surfaces for an extended period of time.

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: Due to your frequent mentions of olive oil, I have shifted over to it as our preferred oil for cooking. I have a question about certain kinds of olive oil, especially the extra virgin olive oils that have an occasional peppery bite when they go down my throat. Please explain why the oils taste this way, and whether such oils are safe to use. -- M.R., Sun City, Ariz.

DEAR M.R.: The peppery bite is not a sign that the oil has gone bad. It's actually a positive attribute, reflecting the presence of the olives' beneficial phytochemicals. But first, some background.

I have had a number of opportunities to watch olive oil being made in Italy, in Greece and in the United States. For those of you unfamiliar with the process, oil gets removed from olives by using specialized presses. The oil that comes out with the least amount of pressure is the "extra virgin" olive oil. This is the darkest, most delicate and flavorful oil, and it is the most expensive.

As pressure is gradually increased the next oil to come out is the "virgin" olive oil. It has less color, but still contains some of the olive's fruitiness. The remaining oil would be the standard, or regular olive oil. Pale in color, this oil has only a hint of olive flavor. Some companies in the U.S. make "light" olive oils that have no distinctive olive flavor whatsoever. Other companies blend the different types or oil to help achieve a more standardized olive flavor. The fatty acids in all the olive oils are approximately 14 percent saturated, 77 percent monounsaturated and 9 percent polyunsaturated.

You mention a concern about safety. Any oil can go rancid if stored the wrong way. Rancidity occurs when the oil reacts with oxygen-forming substances, and this can give the oil a noticeably unpleasant smell and taste. Aside from the off taste, the consumption of oxidized oil can also represent a health risk. The higher the proportion of unsaturated fatty acids, the easier it is for oil to oxidize, but it is heat and exposure to sun and air that are the critical factors for this type of breakdown. This means that oils should always be stored away from sun and heat in a well-sealed bottle.

The olive is the fruit of the olive tree, and the role of the oil is to nourish the developing seed until it can begin to grow on its own. If rancid, the seed would be less likely to grow, so nature equips the olive with a number of protective components: vitamin E and a variety of antioxidant compounds known as polyphenols. These compounds protect the olive and can provide beneficial attributes for us as well.

The people I have spoken with who produce extra virgin olive oil speak with understandable pride about their olives and their oil. They hasten to point out that all olive oil is not the same; it's only the extra virgin olive oil that has the right stuff. Once you understand that it is the extra virgin olive oil that contains the greatest compliment of beneficial phytochemicals, you understand their logic and gain a new appreciation for the various flavors, aromas and the occasional peppery bite.

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: Do you have an opinion about spray vitamins and minerals? When you take them this way, will the body absorb them more efficiently? -- G.P., San Ramon, Calif.

DEAR G.P.: I have found no evidence to favor spray vitamins in general, but there may be an exception for vitamin B-12 under certain circumstances. Vitamin B-12 is a large compound, and its absorption is a complex process. Several specialized proteins and an intrinsic (internal) factor are all needed to bind with the B-12 in our food and facilitate its absorption. In some individuals, especially the elderly and those taking certain medications, the absorption of vitamin B-12 is less than efficient.

If a physician determines that someone is B-12 deficient, one treatment option is the periodic injection of vitamin B-12; this gets away from digestive track absorption issues or dependence on the action of the intrinsic factor. It has also been found that small amounts of B-12 can be passively absorbed through the vascular membranes in the mouth and nose -- as with the spray vitamins you refer to. This could be helpful for those who are B-12 deficient, but it's questionable whether the spray version offers advantages for anyone else.

Then there is the issue of all the other vitamins and minerals in spray form. I could find no evidence that spray versions of other vitamins and minerals get absorbed better or offer any advantages -- aside from those reaped by the company that sells them.

DEAR DR. BLONZ: My husband and I have been trying to start a family and I wanted to know your thoughts regarding the connection between nutrition and male fertility. Please tell me which vitamins are best to help with sperm count and motility. -- F.P., St. Louis

DEAR F.P.: Any of a number of factors can affect male fertility, a major element of which is the production and health of the sperm. If there is a potential problem, it's always best to find out what is going on. I advise that you and your husband discuss your concerns with your health professional before you turn to vitamins or herbs for assistance. Assuming all is OK, and a nutrition approach is warranted, there are a few nutrients of interest.

Zinc is particularly important, and a mild zinc deficiency can lead to a decrease in the number of sperm. Diets low in antioxidant nutrients, like vitamin E, vitamind C and selenium, can make the sperm more vulnerable to oxidative damage. This can limit motility -- the sperm's ability to move around and get where it needs to go -- as well the ability to survive long enough to fertilize an egg. Aside from the above-mentioned antioxidants, there are other valuable antioxidant compounds in various fruits and vegetables. There is also some research to indicate that the amino acids arginine and taurine may be of help. A healthful diet with a daily intake of fresh fruits and vegetables is the best place to start. You can opt for a balanced multivitamin/multimineral, but this can never be thought of as a replacement for healthful food.

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.