DEAR DR. BLONZ: My husband was on a steroid (prednisone) for a number of years. He is now off of it, but it has had an apparent effect on his bones, causing osteopenia. Some calcium products advertised online make claims about regaining lost bone and I don't know whether to be skeptical or not. I am asking you because I want as complete a recovery as possible for my husband, and can't get many specifics from the doctor. -- F.B., Oakland, Calif.

DEAR F.B.: Prednisone is a common type of corticosteroid drug that can affect the efficiency with which the body absorbs dietary calcium. Those on steroids will often have a higher calcium requirement. Your physician or pharmacist should have information regarding these drug-nutrient interactions. Osteopenia is a condition where bone density is decreased, but not to the point where it is diagnosed as osteoporosis. There is general information about these topics, and about medications that can cause bone loss at the National Osteoporosis Foundation (tinyurl.com/8uyv4sf).

As regards nutrient sources, most dairy foods contain a rich supply of calcium per serving. For those choosing to avoid dairy, calcium is available from vegetables such as broccoli, cauliflower and dark green leafy vegetables, such as kale and turnip greens; calcium-set tofu; calcium-fortified soy milk and orange juice; almonds, figs and some legumes. It makes sense for a number of reasons to include green leafy vegetables in the diet.

In your husband's case, it would be reasonable to consider a calcium containing multi-mineral supplement as well. Calcium citrate or calcium citrate-malate are among the best absorbed, but calcium carbonate works well when taken with meals. Remember that it takes more than calcium. Bones are about 90 percent calcium by weight, but other minerals such as magnesium, phosphorous, boron and silicon are needed, and vitamin D is critical to the process. It is also important to maintain a program of weight-bearing exercise as this helps to slow bone loss.

As for regaining lost bone mass, our bones exist in a dynamic state, balanced between the actions of bone-building cells called osteoblasts, and the bone-resorbing actions of calls called osteoclasts. In the first 35 years of life there is a net increas in bone density, which explains why that period is critical to bone health in our later decades of life. Sometime during the fourth decade, this shifts toward the negative. The speed at which we lose our bones depends on diet, lifestyle and genetic predisposition, but it can also be influenced by medications.

In recent years we have learned more about the precise processes at play with the building and breakdown of bone tissue. Through the use of specialized hormones and new medications, we have learned how to slow down the bone-resorbing action of the osteoclasts, while not affecting the bone-building action of the osteoblasts, resulting in a net increase of calcium and other minerals in the bones. There isn't one compound that works in all situations, but it makes sense to speak with your physician to see if anything might be appropriate for your husband.

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: There have been a number of articles lately questioning the wisdom of taking vitamin and mineral supplements. And although it seems to be at cross-purposes, I have also read about the benefits of wheatgrass juice. The product literature states the body will absorb about 90 percent of the nutrients from wheatgrass, which is much more than other foods or pills. Is there any truth to this? Is this food a better source of nutrients than others? -- M.S., Spokane, Wash.

DEAR M.S.: There is no evidence I am aware of that the nutrients in wheatgrass are absorbed more efficiently than those from other whole foods. If by "questioning the wisdom of taking vitamin supplements" you mean questioning the wisdom of relying on supplements to provide all that the body needs, that is certainly something I am in agreement with. I have never recommended supplements as a primary source for nutrients. There is no basis to believe that a lousy diet can be made "healthful" through supplements. With few exceptions, preparing, eating and enjoying whole foods will always be superior. The exceptions might be when there are elevated or specific needs for certain nutrients.

As regards that rate of absorption for the nutrients in wheatgrass versus those in vitamin or mineral supplements, we need to assume that they are constructed so that they will be in solution by the time they reach the absorptive surfaces of the small intestines. Taking a supplement at mealtime aids this process. Supplement manufacturers should provide data to affirm that their products dissolve. In general, there should be a comparable rate of absorption between the vitamins or minerals in foods, and those coming from dissolved supplements. There are exceptions. The absorption of naturally occurring folate in foods turns out to be less efficient than that of the synthetic folate found in fortified foods and supplements. Vitamins tend to be more bioavailable, but minerals are not always efficiently absorbed.

The form a nutrient is in, and the presence or lack of key food components, can affect absorption. For example, calcium is more efficiently absorbed from milk or milk products primarily because the lactose in the milk enhances calcium uptake. The form of iron found in meat, known as heme iron, is more efficiently absorbed than the iron found in fruits and vegetables. Non-heme iron absorption is enhanced in an acid environment, such as that found in citrus juices or tomato sauce. Please don't fret over every last bit of absorption. It does, however, strengthen the argument for variety.

As for wheatgrass juice, it's definitely an acquired taste. Depending on how much is consumed, it can be a source of certain nutrients and it does contain phytochemicals, but I question any acclaim for it being "magical." If you are taking or considering this product, or a similar powdered whole food supplement, I encourage you to visit consumerlab.com to see their recent report on contaminants found in some of these products (tinyurl.com/l3yzswy).

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: Does vegetable oil mellow or otherwise improve with age? We have a number of bottles that we received as gifts but they have been sitting on the shelf for about a year and a half. They were in such beautiful bottles that nobody wanted to open them. Are they still ok to use if they have not been opened? -- J.L., Glendale, Ariz.

DEAR J.L.: Unlike wine, oils do not improve in the bottle. An extra virgin olive oil, for example, will be at its best when first put in the bottle (or can) and it's all downhill from there. Oils should be tightly covered and stored away from heat and light. An unopened container of refined vegetable oil that is properly stored can maintain its quality for about a year. Some oils, including extra virgin olive oils, claim they can last up to two years unopened. After being opened, if stored properly, you have about six months with most oils.

As a general rule, the more unsaturated the oil, the shorter the shelf life. Oils that have been sitting for questionable periods of time should get a sniff and a taste test before being used.

It is always best to buy your oil in containers that match your expected rate of use. If you end up buying in large containers, consider splitting the contents and putting half in the refrigerator for later. Select a container size that allows for very little air space atop the oil as it is stored. To help you keep track, mark the date of purchase, and the date the container was opened, on the label.

DEAR DR. BLONZ: What is taurine? I saw it listed as an ingredient in cat food and didn't give it much thought. Now I find that it is an ingredient in some of those energy drinks. I don't know what it is or what it is supposed to do, and was hoping that you could help. -- R.G., Bend, Ore.

DEAR R.G.: Taurine is a common amino acid, one of the building blocks of protein. Although needed by cats, it is not an essential amino acid for healthy human adults in that the body can make all that it needs. In addition, there are plentiful amounts in meats and fish. There is, however, some preliminary evidence that taurine at higher levels of intake may be of therapeutic value for those suffering from congestive heart failure. It is unclear what taurine adds to energy drinks, especially given the small amounts present in such beverages. 

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.