DEAR DR. BLONZ: My question is about coffee and antioxidants. I had thought that because coffee beans are roasted, they lost their antioxidants in the process. Also, could you explain a bit about the effects of caffeine on the body and how long those effects are felt? -- M.Q., Tucson, Arizona

DEAR M.Q.: Plants produce seeds and package them with enough nourishment to keep them viable until they can begin to grow and gather nutrients on their own. Along with sustenance comes an army of substances (phytochemicals) designed to protect against attacks, whether from insects, animals or the oxidizing rays of the sun. (Interestingly, many “antioxidant” substances have bitter tastes, and this helps to discourage nibbling.)

The coffee plant is no exception to this theme. The ripe, red coffee cherry is the seed for the coffee plant, and it typically contains two green coffee beans. The coffee plant grows in tropical climates, and it contains an array of antioxidant substances for its seeds. Green coffee beans are a rich source of antioxidants. The roasting process darkens the color of the bean and develops the flavor and aroma we associate with coffee. You would think that a high-heat process would be destructive to antioxidants, and roasting does indeed affect the level and type of antioxidants in coffee. What’s been discovered, though, is that the roasting process creates a novel type of antioxidants in coffee beans known as melanoidins, which are not present in the unroasted beans. A study in the June 2002 issue of the Journal of Agricultural and Food Chemistry found that a medium-roasted coffee bean contained more antioxidants than either a light-roasted or a dark-roasted bean.

Regarding caffeine, it won’t surprise you to hear that it stimulates the brain. Its other effects include an increase in heart rate, increased acid release by the stomach, quicker transport of food through the digestive system and a relaxation of the smooth muscles, such as those found in the lungs. Caffeine is also a diuretic, which means it increases the volume of urine the body produces.

Once in the body, caffeine goes just about everywhere. In a pregnant or nursing woman, this may mean it makes its way to a developing fetus or into breast milk.

Because caffeine is a foreign substance, the body starts breaking it down as soon as it appears. The half-life of caffeine can vary. Those who break down caffeine fastest are smokers and, strangely enough, children. It takes them about three hours to eliminate half their body’s caffeine.

The half-life for the average nonsmoking adult is five to seven hours. For women taking birth control pills, it’s up to 13 hours. The half-life in pregnant women is 18 to 20 hours, but returns to normal within a month after delivery. A newborn does not gain any real ability to metabolize caffeine until several days old. Any caffeine received through breast milk during this period has a half-life of about three to four days -- important to consider while pregnant or nursing.

Abrupt withdrawal by a regular caffeine user can lead to symptoms ranging from a simple headache to nausea, drowsiness, depression and reduced attention span. People who drink as little as two cups of coffee a day may experience these withdrawal effects. According to a study in the October 1992 New England Journal of Medicine, half of the 62 coffee drinkers studied experienced moderate to severe headaches when they stopped drinking coffee, and about 1 in 10 reported depression and anxiety.

The symptoms were connected to the caffeine, in that those who discontinued coffee but received caffeine (not placebo) capsules did not report the same problems. However, these symptoms tend to be short-lived, and most can be avoided by cutting back gradually.

Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 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: With the holidays here, I was wondering whether calories from alcoholic beverages such as beer, wine and liquor cause weight gain at about the same rate as calories from carbs and fats. -- F.S., Hayward, California

DEAR F.S.: Calories from alcohol tend to have a more complicated agenda than those from other food components. Much depends on your diet, your overall health and your drinking habits. Regarding strict calorie content, one gram of alcohol contains about seven calories. Compare this with carbohydrates and proteins, which contain four calories per gram, and fat, which contains nine calories per gram.

While there can be brew-to-brew variances, the alcoholic content of beer is about 5 percent by volume, except in states or counties having regulations that limit alcohol content to 3.2 percent. There will be additional carbohydrates in beer, and there can also be an additional amount in other alcoholic beverages, such as liqueurs and finished wines.

Unlike packaged foods, there is no requirement for a Nutrition Facts label on alcoholic beverages. To get a caloric breakdown for a specific beverage, check with the manufacturer. The National Institutes of Health provides a generic calculator at tinyurl.com/ybh4cynr. If you’re only interested in good ballpark figures, you can stop here.

It should be kept in mind that alcohol can become toxic in excessive amounts, so the body has specific enzymes designed to break it down. When we consume alcohol more rapidly than it can be broken down, interim metabolites remain in queue, and this is what brings on the various feelings of inebriation. (Larger people tolerate more because their “queue” is bigger.) An interesting side note to this is that calories from alcohol count more in those who don’t drink on a daily basis. This comes from the fact that when alcohol is consumed on a regular basis, such as a glass of wine a day, the body has some of the needed enzymes at the ready.

There are complexities in alcohol’s metabolic rate that have to do with its ability to proceed down different pathways according to the situation at hand, each having a different impact on the net caloric yield. It’s known, for example, that the metabolites of alcohol can slow down the burning of the body’s own fat for energy; this happens because the alcohol gets preferential treatment. The net effect can be more of a positive fat balance, and alcohol-related fat tends to be deposited in the abdominal area.

Another issue with alcohol is its effect on the heat produced by the body (thermogenesis). Metabolic processes such as digestion are not 100 percent energy-efficient, so it is normal for some dietary energy (i.e., calories) to be lost as heat. (This also explains why we get warm when we exercise.) Alcohol is known to increase thermogenesis more than other foods, but this effect is less robust in overweight individuals, or when paired with a high-fat diet.

A bottom caloric line is that there are about seven calories per gram of alcohol, a number greater than carbohydrates, but lower than fat calories. It is no mystery that the more you drink, the more calories you consume. Excess calories from any source will be stored as body fat, but the alcohol-related excess tends to find a home around the midsection.

Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 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: My doctor determined that I have osteoporosis in my back and hips. (I am 67.) She now wants me to take a prescription bisphosphonate drug. I do not take any medications, and would prefer not to begin. I do take many vitamins and supplements, including calcium and magnesium. Is there anything I can use instead of a drug? -- J.B., Oakland, California

DEAR J.B.: I am not a medical doctor; my training is in biochemistry and nutrition, and my focus is on food, nutrition and health. I cannot therefore give you any medical advice.

I respect your preference for not relying on medication, but it is important to understand that osteoporosis is a nasty ailment. It involves a reduced bone-mineral density that takes decades to develop. Ironically, it develops at a time in life when the body’s ability to build and fortify its bones is on the wane. The class of medications known as bisphosphonates have a demonstrated ability to help the body in this regard.

Our bones are being made and disassembled (resorbed) throughout our lives. From infancy toward adulthood, the process favors the net building of bone, but from midlife toward our senior years, the balance shifts and our total bone mass begins to wane. Osteoblasts are the cells that help build bone, and osteoclasts are the cells that help resorb existing bone, releasing its calcium and other components back into the bloodstream.

The bisphosphonate compounds slow bone resorption by inhibiting the action of the osteoclasts. They have an extremely long half-life, which is science-talk for saying that they are slowly broken down by the body. Depending on the particular bisphosphonate compound selected, they may only need to be taken weekly or monthly. Newer bisphosphonates may only need to be given once a year.

These are medications, and while there is research-based evidence to support their efficacy, there are potential side effects. I advise you to do some research and bring all your issues to your physician so that you can make the right decision for your case. Check out the review by Berkeley Wellness at tinyurl.com/y93l7oz9.

In addition, you need to be eating well and possibly take additional supplements to provide the nutrients needed to build and maintain bones. Aside from calcium, the body relies on magnesium, phosphorous, fluoride and vitamins A, B-6 and D for calcium absorption and healthy bones. “Food first” is an essential philosophy: Eating healthful foods provides benefits far beyond the named nutrients in a supplement bottle.

Finally, our bodies get conservative with resources as we age, lowering the priority of things that aren’t used on a regular basis. The “use it or lose it” theme applies to our bones, and weight-bearing exercise sends a message that you expect your bones to remain strong and on the job. Exercises such as walking, stretching and weight training can help strengthen the body, no matter what age they are begun. However, activities need to be appropriate for your particular situation. Don’t overdo it; seek the guidance of a professional before you begin.

Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 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.