Dr. Keith Roach

DEAR DR. ROACH: I’m an 83-year-old male. I eat a plant-based diet, and I exercise at my local YMCA at least three times a week. I’m concerned that my toes and fingers will turn blue daily, in response to getting cold. My fingertips also become numb. — W.H.
ANSWER: Fingers and toes turn blue due to a change in the blood flow to the area. If an artery is blocked, a whole body part may turn blue, and unless the blood flow is emergently restored, the body part can die. Fortunately, that’s not what is happening in your case.
Fingers and toes that change color in response to cold temperatures do so because of Raynaud’s phenomenon, which is an exaggerated response to the normal reduction of blood flow in order to conserve heat. Many people notice that the fingers will first turn white (due to poor blood flow), then blue (due to loss of oxygen).
Note that deoxygenated blood is red, not blue — that’s a myth. Blood vessels, like veins, appear blue because the blood absorbs red light, and because of the difference in penetration of blue light compared to red light. When the tissue is ischemic (poor or without blood flow), there are no superficial blood-filled vessels that reflect red light, so the entire area appears blue. Numbness and tingling are common.
When the changes come and go, we can be certain of the Raynaud’s diagnosis. Many people with Raynaud’s have it for no particular reason, but it can be found in conjunction with other medical conditions. Getting Raynaud’s at age 83 as a male makes a secondary cause more likely. The list is long, but scleroderma, lupus and cryoglobulinemia are included. It’s worth a visit to your doctor for an exam and some further testing, in my opinion.
DEAR DR. ROACH: I am a 78-year old woman in relatively good health. In November of 2022, my doctor ordered a heavy metal test to be sure my headaches weren’t due to arsenic. I was told not to eat fish for 10 days prior to the test, and followed instructions. The test results showed that my arsenic level was high at 20 mcg/L, and it was thought to be organic, caused by eating fish. I do follow a healthy diet and eat fish three times a week.
I stopped eating all fish for over a month and was retested. This second set of results showed that my arsenic level was less than 10 mcg/L. I was told that this confirmed that my arsenic level was caused by fish and was organic, not inorganic. I am confused now and am not sure whether to still incorporate fish in my diet or to eliminate it completely. Thank you in advance for all of your help. — Anon.
ANSWER: Some foods, especially fish, contain arsenic, but the major form, arsenobetaine, is a nontoxic form of organic arsenic. A level of 20 mcg/L is still fairly low — a single meal of fish can increase urinary arsenic to over 1,000 mcg/L! The number looks scary, but you do not need to worry about it.
The fact that you essentially have no arsenic when you don’t eat fish tells me that you don’t have any worrisome exposure to arsenic. I would not recommend you avoid fish. (I also don’t think the arsenic test result has anything to do with your headaches.)
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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 ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Dr., Orlando, FL 32803.
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