Foods Foods like these one have the most vitamin D: cod liver oil, Herring, oyster, salmon, mackerel, lard, sardine, raw milk, butter, beef liver and eggs. Suntanning Booths Suntanning booths have the extra advantage of giving you an attractive tan. The question is, are they healthy? The two potential problems are burning and skin aging. While it's true that sun exposure has been associated with melanoma, a particularly virulent type of skin cancer, there is evidence that it may not be true: - Most cases of melanoma do not occur on skin that's often exposed to sunlight. About 75% of cases are found in unexposed locations, such as the bottom of the foot. - Melanoma decreases with more sun exposure. - Research from Memorial Sloan-Kettering Cancer Center has shown that the use of sunscreens does not decrease the incidence of melanoma. Supplements The fact that our bodies are designed to obtain D3 from sunlight is indicative of its being the best option, with sunlamps the second choice because they closely mimic the sun's UVA and UVB rays. However, in today's world, that's not practical for many, possibly most, of us. That leaves supplementation as the remaining option. The good news is that supplementation has been shown to effectively increase serum blood levels of D3. The downside is that it's possible to overdose on D3 this way. (When sunning or using lamps, it's impossible to overdo D3, because excess is destroyed on the skin by the sun's rays.) In truth, this is extremely unlikely. You'd have a hard time finding a doctor who has ever seen a case of Vitamin D toxicity. Nonetheless, you should be aware of the potential and have your blood levels tested to assure they don't go over 100 ng/ml. The question is, of course, how much should you take? This is where having your blood tested, as described in Sunlight--Required Nutrient, Not a Health Risk, comes in. Be aware that, as a fat-soluble hormone, D3 is stored by the body, not excreted when in excess, as with Vitamin C. Therefore, you can approach the problem of inadequate serum levels by taking high doses, and then leveling off until you find a good maintenance dose.