DEAR DR. BLONZ: My boyfriend works at night and then takes melatonin to help him sleep during the day. For a number of weeks, he has been taking 3 milligrams a day. I told him that I wouldn't personally take it every day, but he said that otherwise he wouldn't get sufficient sleep. His job requires him to be alert, so getting enough sleep is crucial. I have looked up melatonin online but keep finding conflicting information. What do you recommend? -- J.K., San Jose, Calif.

DEAR J.K.: I question the use of melatonin on a regular basis for this purpose, especially if your boyfriend's work schedule is consistent. Melatonin should not be thought of as a sedative or a sleeping pill; it is more along the lines of a hormone that can facilitate "re-education" to reset your body to a new sleep schedule. Once the sleep pattern has been established, it has done its job. There are legitimate concerns about the taking of an unneeded hormone as a part of one's daily regimen.

Our bodies respond to daylight and darkness, and the hormone melatonin plays a role in the sleep/wake cycle. It is released by the pineal gland after we shut our eyes and go to sleep, which usually occurs at night in the dark. Seeing as your boyfriend is sleeping during the daylight hours, the room where he sleeps should be completely dark. If he routinely wakes during his "night" to visit the bathroom, that room should, if possible, be dark as well. When he wakes up at the end of his sleep, he should get some exposure to bright light. If there is no sunlight when he wakes for his "day," he might consider buying a full-spectrum light. The idea here is that he should do his best to educate his body that his pattern is the norm. When it is his sleep time he should avoid computer monitors, televisions, e-readers or tablets with bright screens, as this light can inhibit the body's normal melatonin production. (This is good advice for anyone having trouble getting to sleep.)

Your boyfriend should check with his physician to make sure that melatonin, or any other product, will not present a problem with his health profile. Thinking beyond medicinal fixes, eating well and exercising both help with sleep by decreasing stress, which is a potent sleep-robber. Exercise also helps tweak the body toward a regular activity/regeneration cycle, sleep being where regeneration takes place.

Other ideas: There are a number of relaxation techniques and tapes that may be of help. A warm glass of milk before bedtime is a tried-and-true remedy, as is a warm bath. Tryptophan, an amino acid, may also help -- it's the precursor to the neurotransmitter serotonin, which can encourage relaxation.

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'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.