DEAR DR. BLONZ: I've always thought that if I have all my fruits, vegetables and grains -- organic, when possible -- along with other foods in the amounts recommended, I should not need any dietary supplements. Recently, I attended an anti-aging conference where I was told that the soil throughout the United States is 85 percent depleted of its vitamins and nutrients. They said eating organic does not mean you are getting your fruits and vegetables from nutrient-dense soil. Is this a fact? I am hoping you can help me identify areas of the country, or the world, where a person can be sure to get produce with the proper nutrients. -- R.V., San Dimas, California

DEAR R.V.: The information from that anti-aging conference was off the mark. While I am definitely pro-organic and support it when possible, it is better to eat conventionally grown produce than to limit your intake of fruits and vegetables.

The often-heard "soil-depletion" argument can be very misleading. In addition to their need for sun, water and proper temperature, fruits, vegetables and grains -- whether grown organically or through conventional methods -- require certain nutrients to develop. If a plant's essential minerals are not in the soil, for example, the plant simply won't grow, or it will fail to develop normally.

Minerals that aren't needed can also be taken up by a plant. Foods grown in selenium-rich soil, for example, often contain more of this mineral than the same plants grown in selenium-poor soil. A plant's mineral content can also vary according to the time of the growing season and the length of time the plant has had to grow.

The idea of "vitamin-depleted" soils makes even less sense. Plants do not get their vitamins from the soil; they, along with other phytochemicals, are synthesized within the plant itself. The amount of a particular vitamin found in a fruit, vegetable or grain is determined by the plant's genes, not by the amount present in the soil. After harvest, vitamin content can decline with time, and some vitamins can be affected by cooking.

It then follows that there really isn't a specific area of the country (or the world) where a person can be sure that the fruits and vegetables have the "proper nutrients and vitamins." If you are concerned about the adequacy of your diet, if you have health issues or are at risk for certain chronic diseases, there are a number of websites where you can enter the foods you eat and get a report of nutrients consumed. As is typical of today's online "diet," some of these sites charge money, while others provide the service for free -- but with a "side dish" of advertisements.

Variety is key wherever you live, and we are blessed with a transportation system that brings us foods from all over. Eating well is the cornerstone of good health, and a good diet places you head and shoulders above the vast majority of your peers.

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: My partner had an emergency heart valve replacement and is now on the blood thinner Coumadin, perhaps for the rest of his life. The surgery saved his life, so we are extremely grateful, but he has been told not to eat green vegetables anymore. This is proving very hard, as we love our veggies. Eating just yellow and white ones doesn't allow much variety. Are there any web resources, books, charts or cookbooks that would show us how to insert some green veggies occasionally, while keeping his blood levels correct? -- J.B., Seattle

DEAR J.B.: I can only imagine the difficult times you have gone through, and am pleased to hear about the success of the procedure. There may be other anticoagulant (blood thinner) options to consider; your partner should discuss this with his physician. My answer will address Coumadin, since that is what he's currently taking.

First, some background. Coumadin, the brand name for warfarin, gets its abilities as a blood thinner from its opposition to vitamin K, which plays an integral role in blood clotting. The warning against green, leafy vegetables stems from the fact that vitamin K is present in these foods. By increasing the vitamin K in your diet, you could overwhelm the ability of the Coumadin to do its job.

The appropriate dose of Coumadin is determined through a series of blood-clotting tests. These are done with the patient's blood, so they will reflect his normal eating habits. From that point on, the key is to hold constant any substances that would affect blood clotting. It is not that your partner needs to completely eliminate vitamin K -- rather, once his Coumadin dose is determined, he should keep his level of vitamin K as constant as possible.

Other Coumadin-related advice includes checking with his doctor on other medications he might be taking. Aspirin, for example, affects blood clotting. Certain herbs can also interact with Coumadin (and blood clotting in general), so they should not be used without prior medical clearance. A list of suspect herbs would include ginseng, garlic, ginkgo, dan shen (salvia), devil's claw, dong quai, fenugreek, horse chestnut, papain (from papayas), chlorella and St. John's Wort.

You can download an extensive list of foods containing vitamin K at tinyurl.com/z92bfl7. This list comes from the coumadin.com website, which includes other pertinent information about the medication.

There are also a number of cookbooks that may help. One I am familiar with is appropriately named "The Coumadin Cookbook," now in its fourth edition. The author is a medical doctor who wrote the book after his wife was put on Coumadin, and they faced the same problems that you are now experiencing.

Your partner has been given the remarkable gift of a new heart valve -- something that would not have even been possible years earlier. If all that's needed to make it work is to watch the foods he eats, so be it! I wish you both good health and good luck.

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 wondering if I get the same benefits from drinking iced tea as hot tea. Also, does the decaffeination process change the tea's beneficial characteristics? -- D.D., San Jose, California

DEAR D.D.: Assuming they are made from the same tea leaves brewed in the same way, there should be no significant difference in the health benefits between iced tea and hot.

The decaffeination process, however, is a mixed bag; there is the possibility of losing some of the tea's beneficial phytochemicals, depending on how the tea is processed. Some companies use steam, while others remove caffeine through the use of solvents.

One animal study checked the effects of black and green teas -- both regular and decaffeinated -- against the development of skin cancer. It found that regular black tea was most effective, followed by the green tea, then the decaffeinated black, then the decaffeinated green tea. They all had beneficial effects; it was just a matter of degree.

Of interest here is the fact that the caffeine itself might have some anti-cancer properties. There have been studies that have found that adding caffeine back to the decaffeinated tea "restored" much of its anti-cancer abilities. Indeed, even caffeine was found to have an ability to prevent certain cancers on its own.

Don't take this as an endorsement of caffeine as an anti-cancer agent, but more to highlight the difficulties in understanding how complex substances work in the body. Also consider that these were specialized research studies where relatively large amounts of tea extracts or solids were given for a short period of time. It is unclear how much we can generalize from the studies. The takeaway should be that tea is a healthful beverage to be enjoyed any way you like it.

DEAR DR. BLONZ: I hope you can help me with an embarrassing problem I have with the back of my hands. It seems all I have to do is tap them with my finger or hit them by mistake, and they bleed under the skin, causing a very ugly bruise. Are there any supplements I can take? -- J.D., New York City

DEAR J.D.: The blood-clotting mechanism is a complex series of biochemical reactions, the end result of which is the creation of an insoluble plug that prevents blood cells from leaking out of the vessels. In the case of a bruise, the bleeding takes place under the skin.

As we age, our skin tends to become thinner. So, too, can the walls of our blood vessels. A weakness in our blood vessel walls can contribute to an increased tendency to bruise. This can occur in good health, but a number of health conditions, medications and dietary issues can also play a role.

Discuss your bruising tendency with your physician to verify that there isn't any underlying condition or medication that may be to blame. From a dietary standpoint, I would aim for at least five servings of fruits and vegetables a day. Vitamin C and the other nutrients found in many of these foods are involved with the formation of collagen, a substance used to form blood vessels. Until you have additional information about possible underlying mechanisms and factors to consider, it's best to keep your focus on foods -- not supplements.

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.