DEAR DR. BLONZ: I have always wanted to know if there was any connection between getting a cold and having a cold sore. What can be done with the diet to help prevent cold sores? -- J.B., Davis, Calif.

DEAR J.B.: Although it is referred to as a cold sore (or fever blister), the connection with an actual cold or fever is minimal. About the only thing they have in common is that a virus is responsible, but it's not even the same virus. The cold sore is brought on by the activities of a specific virus -- herpes simplex virus 1 (HSV-1) -- while the common cold is caused by a different family of viral organisms. Most of us get over a cold in about a week and the cold virus is history. A cold sore may disappear in the same amount of time, but HSV-1 tends to hang around, lying dormant in our nerve cells while it awaits the next opportunity to attack. It is quite a common infection; in fact, the National Institutes of Health report that most adults are infected with HSV-1 by age 20 (tinyurl.com/pxeqa).

A possible correlation between having a cold and developing an outbreak of cold sores could be the fact that our immune system gets taxed by an ongoing cold, and this would provide an opportunity for the herpes virus to come out and play. Other factors that can provoke a cold sore outbreak include stress, fever, an injury to the lips or mouth or excessive exposure to cold, sun or wind.

There are antiviral medications that can help fight an infection, so you can check with your physician if this is a recurrent problem. As for your diet question, there does appear to be a dietary connection. The HSV-1 virus may have an appetite for the amino acid arginine -- found in chocolate, grains, nuts and nut butters -- while having a distaste for the amino acid lysine, which is found in eggs, potatoes and dairy products. If you tend to suffer from cold sores, you might consider increasing the ratio of lysine to arginine in your diet, particularly if you feel an outbreak coming on. A more convenient approach would be to take a lysine supplement.

DEAR DR. BLONZ: Are there any nutrients that could contribute to the tendency to develop dark circles under the eyes? -- S.Q., Sonoma, Ariz.

DEAR S.Q.: Darkness under the eyes can be brought about by a number of factors. Perhaps the most common cause is a natural thinness in the skin under the eyes. The skin isn't dark, but at that location it is easier to see the vascular bed underneath. This trait can run in families and it doesn't necessarily reflect any health problem. If one is fatigued or under stress, the skin can become pale and this could accentuate the darkness. Then there is the fact that facial skin, and the subdermal fat layer, can thin a bit as we age. Unfortunately, aside from the general nutrients needed for normal health, there are no vitamins, minerals or herbal supplements that have demonstrated an ability to help eliminate this problem.

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 work at a large manufacturing company and there seems to be an increasing number of people with diabetes and weight problems. One of my responsibilities is to oversee the break room and I want to have appropriate snacks available for diabetics. I would imagine that more fruit would help, but what prepackaged snacks would be best to have? -- R.D., via email

DEAR R.D.: The Centers for Disease Control has maps comparing the state-by-state levels of diabetes and obesity in the U.S. in 1994, 2000 and 2010 (tinyurl.com/9vdomyl). A look at this document reveals that your observations are as accurate as they are unfortunate. Having said that, healthful snack foods for diabetics don't differ much from those that would be recommended for others. You should aim for nutrient-dense, great-tasting foods that can serve either as a bite between meals or a meal substitute. The key for diabetic people, especially those who require insulin, is the availability of nutritional information about the food.

Good suggestions for snacks would include fresh fruits, as you mentioned, together with an assortment of nuts, seeds, pretzels and dried fruits. Keep a log of what you add, and when, so that you can track preferences and maintain freshness. Prepackaged snacks containing these foods would add a measure of convenience, but I would advise you to stay away from overly sugared snack products or any made with partially hydrogenated fats; check the nutrition facts panel and the ingredient list.

If you have a refrigerator in your break room, you might consider stocking some different yogurts or fruit/vegetable juices. I would also stock a selection of meal replacement bars; they can provide a good source of balanced nutrients and they can help fill in for any missed meals.

In all cases you should have a sheet that contains a nutrient breakdown of the various foods. You can get these from the labels, or from websites such as ndb.nal.usda.gov or nutritiondata.self.com.

DEAR DR. BLONZ: I was upset to read that some B vitamins stimulate the growth of fat cells. Could you tell me which ones do this? -- N.E., Waukesha, Wis.

The B vitamins are essential for energy metabolism and the growth and development of all cells, including fat cells. They should not be thought of as stimulants to fat-cell growth; that aspect is dependent on the balance between the amount of energy consumed and the amount required. I don't know where you read this, but the document seems to be a bit thin on the basic facts.

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 46 years old and have been terribly overweight for over 10 years. I finally decided to get a gastric bypass, and had the surgery in late June. I quickly recovered, but my body is now in a state of malabsorption. Do you know of anything in a liquid form that would provide megadoses of vitamins and minerals for someone like me? -- P.S., San Jose, Calif.

DEAR P.S.: For those unfamiliar with this procedure, a gastric bypass surgically restricts the volume of food that the stomach can contain. The aim is to assist the individual to be satisfied with eating less food and thereby achieve significant weight loss. The U.S. National Library of Medicine has a page describing various gastric bypass methods and issues: tinyurl.com/5gdlgh

A gastric bypass ushers in a radical change to an individual’s relationship with food, so it is only recommended for a motivated patient whose excess weight represents a serious health threat. After the bypass, a patient has to eat slowly and chew food well because the stomach can no longer operate with the same level of efficiency. Some nutrients may not be as efficiently absorbed following a bypass, which is called malabsorption. If left untreated, vitamin and mineral deficiencies can result. Vitamin and mineral supplements can be recommended, and the physician will usually monitor blood levels of the various nutrients.

I am not a medical doctor and this is not an area in which I specialize, but it certainly makes sense that you search out a high-potency supplement, perhaps one that could be taken in liquid form. You might consider one of the powdered multivitamin/multimineral supplements. Most are well-balanced, containing all the essential vitamins and minerals, and they could be taken as a daily drink or smoothie. Be sure to discuss any products with your physician or a dietitian who specializes in this area.

DEAR DR. BLONZ: The other day, my husband heard that when cooking vegetables in the microwave, you lose the nutrients. Is this just another health rumor, or is it true? I cannot believe that this information is just now coming out after having microwaves around for decades. I would appreciate your take on this. -- A., Concord, Calif.

DEAR A.: This is a rumor -- and unfortunately it is quite widespread. The differences in nutrient composition between fresh and cooked food is based on the level of heat and the time of exposure. The next factor is whether the food is submerged and cooked in water and if the cooking water, which can contain some of the water-soluble nutrients, is then discarded.

There is nothing especially destructive about microwaving, provided you do not overcook your food. In fact, microwaving is similar to steaming -- both are low on the nutrient-destruction spectrum. The most important factor is that you are eating and enjoying the bounty of fresh vegetables for good health.

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.