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.

DEAR DR. BLONZ: I take vitamins with dinner, along with a 1,000-milligram calcium pill. I had thought this was the best way to get my daily requirements, but now I hear that we only absorb 500 mg at a time. Is that true? How do you recommend getting one's calcium? -- D.T., Phoenix

DEAR D.T.: There is a specific mechanism by which calcium gets absorbed from the digestive tract, and the 500 mg at a time max is a reasonable approach. It turns out that on average, the human body only absorbs about 20 to 30 percent of the calcium it ingests. This can rise to 50 to 60 percent during adolescence, pregnancy and lactation, but these are periods of unusual demand where the body has its absorptive machinery set on "high." All this absorptive inefficiency is taken into account during the setting of calcium dietary requirements for different age groups.

You are probably getting some calcium from your food, but when taken as a supplement, it makes sense to divide it up among two or more meals. Here are some other steps you can take to help increase your absorption of calcium and other minerals.

-- Get adequate amounts of vitamin D. This vitamin is involved in the production of a calcium-binding protein that helps transport calcium through the intestinal wall. Note that your intake of vitamin D doesn't have to be at the same meal as the calcium.

-- Have enough dietary protein, but don't overdo it. An adequate intake of protein is essential, not only because protein is needed for tissue growth and enzyme production, but because calcium tends to form easily absorbed salts with the amino acids in protein. However, excessive intakes of protein can create an acid burden that drains calcium from the body.

-- Lactose can help, as long as you're not intolerant. This carbohydrate found in milk products can enhance calcium uptake. The effect is tied to the activity of lactase, the intestinal enzyme that helps break down the lactose. However, lactose intolerant individuals -- those who don't produce enough of their own enzyme to digest the lactose -- will not realize this particular benefit.

-- Mealtime is best. The acid environment created during digestion helps keep calcium in solution and ready to be absorbed.

-- Keep phytates and oxalates away. Phytic acid, a naturally occurring compound found in the outer hulls of cereal grains, forms an insoluble salt with calcium and other minerals. This doesn't apply to whole-grain breads, as the phytic acid is broken apart during the leavening process. Oxalic acid, found in rhubarb, swiss chard, cocoa and beet greens, also forms an insoluble salt with calcium. If a meal contains any of these foods, make sure that it's not your only calcium-containing meal of the day.

Aside from all these details associated with calcium absorption, it is also important to appreciate that physical activity improves bone mineralization. Staying active helps to keep that calcium in your bones where you want it.

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 am a retired male, 66 years old, 5'9", 142 pounds and take no doctor-prescribed drugs. In your opinion, what is the nutritional value of a daily consumption of 8 ounces of Low Sodium V8 vegetable juice? I try and eat healthfully, i.e. no red meat, but don't always get my veggies. -- M.M., Sun City, Ariz.

DEAR M.M.: No problems with the V8 juice. I encourage people to eat whole foods: These are the packages made by nature that contain all the nutrients and phytochemicals needed for that particular plant to survive amidst the insults and ravages of nature. You lose a bit of these nutrients when you take steps back to processed food, but your vegetable juice has been only minimally processed. This is not to say that all processed foods are bad; read the labels to see what they are made of. The key is to have real foods -- vegetables, fruits and whole grains -- serve as your foundation. With that as a basis for your diet, the door opens to adding other items. I have no problems with red meat following such an approach.

DEAR DR. BLONZ: Is eating beef liver dangerous? -- J.S., Canada

DEAR J.S.: The liver is a remarkably resilient organ and it is endowed with an ability to regenerate. It has an undeserved reputation as a toxic waste dump, and while it does serve as a clearinghouse for unneeded or unwanted substances, it doesn't hold on to these substances. Its job is to take them out of the bloodstream, make modifications where possible and then send them out of harm's way. If, however, there is an ongoing exposure to dangerous compounds, the liver will be in the midst of the battle. Thus, the health of the animal that the liver comes from is key.

For people in good health with an otherwise healthful diet, an occasional serving of liver should not be a problem. A healthful option is to seek out liver and other meats from grass-fed, organically raised cattle and organic, pastured poultry. Seek out a provider that sells in your area, one who follows a stated philosophy of raising his or her animals on healthful pastures without using hormones or feed additives. You can often find such providers at farmers' markets and natural food stores.

DEAR DR. BLONZ: Maybe you can help me with this fiber problem. In the November 2011 issue of the UC Berkeley Wellness Letter, an article on eating vegetables suggested pureeing veggies and including them in other foods. My concern is about getting the maximum amount of fiber out of the veggies. Does pureeing them reduce the amount of fiber, or is it intact regardless of how the veggie is eaten (raw, steamed, pureed, etc.)? -- V.R.C., via email

DEAR V.R.C.: The process of making a puree out of fresh vegetables (or fruits) does not have a significant impact on its fiber content. Of course, this does not apply to juicers where the fibrous portion of the food is discarded.

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.