DEAR DR. BLONZ: There is a memory supplement being promoted by a doctor (at least it is someone with Dr. before their name). There are positive testimonials from people, and many seem to have started with the same concerns I have. I admit I have this temptation to try it, but there are many of the red flags you have previously discussed. -- B.G., Lisle, Ill.

Dear B.G., Organizations are out there selling dubious advanced college degrees to anyone with a bank account. This means there are people calling themselves "doctor" without the necessary training to know what they are talking about. This can be deadly serious when it involves issues related to health. Not so much that the products being hawked are necessarily dangerous, but that people may be kept away from accurate diagnosis, and a once-treatable condition can become a more serious problem. While there are online courses by credible institutions, and these can indeed help one complete credits needed to achieve a degree, it's essential to find out what you're dealing with.

The literature you included with your letter contains plenty of promises, but little evidence to back up the claims. There's also no information about the products' ingredients. The individual in charge goes by "doctor," but it never reveals what type of doctor he is. All it says is that he is an internationally known authority. Questions that come to mind include "Known by whom?" It reads like a scam. Based on what you sent, it is nothing that I would buy or recommend.

To avoid being taken, we need to be alert to the different ways that questionable products can be foisted upon the public. This particular product uses a common strategy; namely the use of a collection of convincing true-to-life testimonials. The pitch follows the line that "it worked for them, so why not for you?" Add the support of someone with pseudo-credentials, and you end up with impressive marketing clout. Here are a few basic guidelines:

1. Make sure that the people giving you advice are the real deal. If they're passing themselves off as experts, find out if this is the case by checking for their accomplishments outside of the particular organization selling the product.

2. Put up those antennas. Ask questions if your instincts tell you something is not quite right, or you want more background on the product, the scientific personalities or the evidence being proffered.

3. If a particular scientific concept is the basis for the product, check to see if this concept is shared by experts not associated with the product or company.

4. Always keep your physician up to speed with what you are taking. There can be side effects or interactions with medications that need to be considered.

If you ever uncover health fraud, report it immediately to the appropriate authorities; search for Consumer Complaint and Protection Coordinators to get contact information for the oversight agencies in your area. Finally, we need to always be cognizant of the fact that this is a buyer-beware market. If you fall victim to an economic fraud, you've lost your money. But if it involves your health, the risks and potential losses can have life-altering implications.

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 keep receiving information about oxygenated water and wanted to know your thoughts on this. Could you send me the straight scoop? -- O.S., San Diego

DEAR O.S.: Hope this doesn't burst your bubble, but there is no evidence to support any belief that oxygenated water will deliver anything more than an expensive burp. We get our oxygen by breathing, not by swallowing.

Consider that oxygen is not that soluble in water, which means that there is not going to be much of it in a serving. Any oxygen forced into the water under pressure will tend to bubble away when the container is opened and the pressure is relieved.

Next, we have the fact that this product is swallowed, not inhaled. The small amount of oxygen that ends up in your digestive system is not going to have a measurable effect on the level of oxygen being delivered to your muscles or brain via the bloodstream. Without any support for the claims being made, and the lack of scientific logic working against it, "oxygenated water" does not look like a winning concept. That being said, a hefty marketing effort always tends to entice some to make a purchase.

DEAR DR. BLONZ: What are GMPs, and how do they apply to dietary supplements? -- R.S., El Cerrito, Calif.

DEAR R.S.: GMP stands for Good Manufacturing Practices. They have been making their way to the marketplace for years on foods, and now dietary supplements. They are a rather lengthy set of government regulations including specific rules about the identity, purity, quality, strength and composition of the ingredients, along with the manufacturing, packaging and storage of the product. GMPs are concerned with the way dietary supplements are manufactured; it is important to appreciate that they have no bearing on the actual safety and effectiveness of the supplements themselves. This being said, it is about time that we can at least be assured that what's on the label is actually in the bottle, and what is in the bottle is accurately described on the label.

We already have GMPs for foods, food additives, pharmaceuticals and even cosmetics, but there had never been any in place for dietary supplements. I consider this to be an important consumer protection measure. Go to tinyurl.com/kyyl5v9 to view the most recent set of dietary supplement GMPs.

DEAR DR. BLONZ: Is it true that cottage cheese consumed by the elderly will leach calcium from the bones? I heard this at a discussion and am concerned because I like to have cottage cheese and fruit for lunch. -- N.N., via email

DEAR N.N.: One half-cup of low-fat (1 percent) cottage cheese contains 14 grams of protein, 1 gram of fat, 3 grams of carbohydrates and 69 milligrams of calcium. It is not a good source of calcium like other dairy products, but there is no reason to believe that cottage cheese will leach calcium from the bones of individuals -- in any age group.

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: Lean ground beef costs quite a bit more than regular. The fat drains out when you cook it anyway, so is it worth it, health-wise, to buy the more expensive type? -- C.S., Kansas City, Mo.

DEAR C.S.: To best answer your question, we will need to do some math. Let's start with two quarter-pound patties of uncooked hamburger (113 grams each). The first is of meat that is 75 percent lean, and the second is 95 percent lean. The 75 percent lean meat contains about 28 grams of fat, 18 grams of protein, 85 milligrams of cholesterol and 66 grams of water. The 95 percent lean patty contains 5.6 grams of fat, 24 grams of protein, 70 milligrams of cholesterol and 83 grams of water. At this point, we see that the leaner meat has more water and protein, but less fat and cholesterol.

The cooking process will cause both patties to lose both water and fat.

The 75 percent lean meat drops from 113 grams to 70 grams in weight (a 38 percent decrease). After being cooked, it will contain about 13 grams of fat (a 54 percent decrease), 18 grams of protein (no loss here), 62 grams of cholesterol (a 15 percent decrease) and 39 grams of water (a 41 percent decrease).

The 95 percent lean meat will drop from 113 grams to 82 grams in weight (a 27 percent decrease), and will contain 5.4 grams of fat (a 4 percent decrease), 22 grams of protein (an 8 percent decrease), 62 milligrams of cholesterol (an 11 percent decrease), and 54 grams of water (a 35 percent decrease).

They both weighed the same before cooking, but after cooking, the 75 percent lean meat weighs 70 grams and contains 189 calories. The 95 percent lean meat weighs 82 grams and contains 137 calories.

The patty made from the leaner ground beef gives you more to eat, and while they both contain a comparable amount of cholesterol, the lean beef provides more protein and less fat.

As to which is worth it health-wise, much depends on the rest of the foods you have on your plate that day. Then there are other considerations such as your food budget, where the beef came from, and how that rancher treated the animals and the land on which the cattle were raised. Granted, this is big-picture stuff, but I believe it all deserves consideration.

DEAR DR. BLONZ: What is the bioavailability of the calcium carbonate in almond milk, given that there's no lactose in that kind of milk? And what's the bioavailability of calcium in real cow's milk if I pour it on cooked nine-grain cereal? Does the wheat in this cereal somehow limit the amount of calcium the body can absorb? -- R.L., Berkeley, Calif.

DEAR R.L.: There will be slightly less bioavailability with the calcium in fortified milk substitutes, such as almond or soy milks, than with the calcium in dairy milk. Breakfast cereals, when served with any calcium-containing beverage, enhance calcium intake by the very inclusion of that source of calcium. A whole-grain cereal may decrease calcium absorption to a minor degree, but many cereals are fortified with their own calcium. None of these factors should in any way be considered game-changers.

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.