I have become a big fan of iced coffee: I drink it in just about every coffee shop I pass. I have had "diet" iced coffee with 1% milk and sugar substitute, "diet" with 1% milk with sugar, and iced coffee with 3% milk and sugar. I have also had the "diet" iced coffee in the Fro Yo ice cream stores made with low-fat yogurt, which I suspect is loaded with sugar. I have asked in every store what the calorie count is, and no one has ever been able to tell me other than: "It's diet, so how many calories can it have?" How can I know how many calories I am drinking when I keep "treating" myself? It is important that I know, as I am trying to diet and take off some weight. I will appreciate any advice you are able to give me. - P.K., via e-mail Dorit Adler, the chief clinical dietitian at Hadassah University Medical Center and Hadassah Optimal, replies: It's impossible for you or me to know how many calories are contained in each kind of iced coffee. Only the person or the company that makes it can know, because they know the ingredients, such as how much sugar and whether there is real cream in it. Some restaurants and chain stores are now listing the number of calories in what they serve, and this is exactly what their customers are entitled to know. How many calories are in a particular iced coffee also depends on the size of the glass or cup. Drinking iced coffee several times day, even if the milk is 3% or only 1% or based on low-fat yogurt, can add up to a lot of calories and add a lot of weight. So be careful - and insist on knowing exactly what you're drinking. I was very interested to read your Q/A recently about toenail fungus and its treatment. I have just been prescribed a three-month course of Terbafine tablets (250 mg.) for a toenail fungus, with strict instructions to take it every day without fail and with my midday meal. My question is, on fast days such as Yom Kippur, when I will not be eating a midday meal, how do I take the tablet? - G. K., Ramat Gan Dr. Julian Schamroth, a veteran Jerusalem dermatologist, advises: Take one on the eve of the fast and the second right after the fast. Taking the pill a few hours late is not a problem. I am a 51-year-old man from a family with heart problems, but so far I am healthy. I keep seeing ads promoting omega-3 (fish) oil tablets, and I want to know whether the oil is really as beneficial as claimed. - R.V., Haifa Judy Siegel-Itzkovich comments: The August issue of the Mayo Clinic Health Letter deals with omega-3, which really is becoming a popular food supplement. It notes that while a heart-healthy diet has become synonymous with plenty of fruits and vegetables and little fat and cholesterol, many people do not follow these recommendations for their diet. Experts believe that omega-3 fatty acids should be part of a heart-healthy diet. They are a form of polyunsaturated fat whose main benefit is its ability to reduce the risk of heart rhythm problems in certain groups of people, thus reducing the risk of sudden cardiac death. In addition, omega-3s may help reduce triglycerides, lower blood pressure slightly and reduce blood clotting. Two kinds of omega-3 - docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) - may benefit some people with established heart disease or high triglyceride levels and can have an anti-inflammatory effect for people with rheumatoid arthritis. In addition, DHA is being studied to see if it can slow the progression of Alzheimer's disease. The best source of omega-3s is fatty, cold-water fish such as herring, mackerel, salmon and tuna. Plant oils, such as canola and flaxseed, also are sources of omega-3s. But as eating this fish is not convenient to many people, and some do not like fish, one can take the capsules. However, consult your doctor before taking such supplements and about the dosage. Taking more than three grams of fish oil a day may increase the risk of bleeding, worsen heart rhythm problems in those who have arrhythmias or cause other side effects. The capsules aren't cheap, and the amount of DHA and EPA in supplements varies widely from one brand to another. Rx For Readers welcomes queries from readers about medical problems. Experts will answer those we find most interesting. Write Rx For Readers, The Jerusalem Post, POB 81, Jerusalem 91000, fax your question to Judy Siegel-Itzkovich at (02) 538-9527, or e-mail it to email@example.com, giving your initials, age and residence.