Dear Dr. Roach: I walk outside almost every day for at least an hour. I cover myself from head to toe 鈥� long pants and long sleeves, with the backs of my hands covered and a wide-brimmed hat with a bandanna covering my neck and lower chin. With sunglasses on, ready to go, my husband jokes that I look like I am going to rob a bank! But after numerous skin cancers, I do not want any sun. Therefore, the only skin exposed to the sun is on my 10 fingers. Is that enough exposure to get a daily dose of vitamin D?
J.P.
It is very difficult to get vitamin D from the diet, so the body makes its own in the skin, when exposed to sunlight. However, people differ in their ability to make vitamin D (in general, lighter-skinned people are better able to make vitamin D than darker-skinned ones). Where you are on the planet and at what season also determines how effective the sunlight is at helping your body do that. So, the amount of skin that needs to be exposed depends on a great many factors.
People who wear sun-protective clothing, like you do (and those who do not go outside at all) are at high risk for having vitamin D deficiency. I understand your reasoning given your history of skin cancer, but I would recommend either taking a vitamin D supplement (1,000-2,000 IU a day is common) or getting your vitamin D level checked by your doctor. From what you are saying, I doubt that you have enough skin exposure for vitamin D.
Dear Dr. Roach: What does 鈥渢hickening鈥� mean regarding a CT scan of a gallbladder? Does this call for a biopsy? What is cholelithiasis?
Anon.
We don鈥檛 often think of the gallbladder when everything is going well. The gallbladder is a fairly simple organ, whose job is to store the bile made in the liver. When we eat, the gallbladder releases the bile at the right time to help us digest food, especially fats, properly. By far, the most common problem of a gallbladder is the presence of gallstones. These crystals of bile salts and cholesterol can block the bile ducts, so when the gallbladder squeezes to release bile, it causes pain, usually in the area of the gallbladder, which is in the right upper quadrant of the abdomen. The symptoms are most likely to come after a fatty meal, which is a strong stimulus to the gallbladder to squeeze.
Gallstones (choleliths, literally 鈥渂ile stones鈥� from Greek) can be seen in the gallbladder by an imaging study, such as ultrasound, but thickening of the gallbladder wall is highly suggestive that the gallbladder has been squeezing against a blockage. In a person with symptoms suggestive of inflammation of the gallbladder (鈥渃holecystitis鈥�) and presence of gallstones (鈥渃holelithiasis鈥�), definitive surgery to remove the gallbladder would normally be the next step, rather than biopsy. People with focal thickening of the gallbladder wall but without symptoms of cholecystitis might be suspected of a gallbladder tumour, and biopsy might be indicated in that situation.
Incidentally, some people might wonder how the body manages without a gallbladder. The liver takes over the job of releasing bile at the right time, and most people will have no further symptoms within a few months of surgery.
Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to [email protected].
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