Side effect of increased cholesterol

Q. I have been taking glucosamine hydrochloride and chondroitin sulfate for knee joint pain. My cholesterol has always been a little over 200.

Since last summer, my cholesterol has jumped to 435. The only thing that has changed is that I take this arthritis supplement daily.

I read on your website that others have had a similar problem. I now have hope in figuring out why I have such dangerous cholesterol levels. Is there up-to-date information?

A. We first heard about this concern over 20 years ago. A reader reported: “I have been taking glucosamine for arthritis this past year and it has helped. However, the side effect has been increased cholesterol. My last count was 346, up 100 points from before.” Since then, we have heard from others that their cholesterol rises when taking glucosamine.

Researchers have attempted to study this phenomenon; they have not identified a problem (BMC Pharmacology & Toxicology, online, Oct. 10, 2012).

We can only speculate that certain people may be especially sensitive to glucosamine. Studies might not pick up such individual reactions.

Q. I’ve read that coffee can assist in staving off dementia. Since I am 70 years old and still have most of my mind, this is of interest.

However, documentation and experience indicate that caffeine aggravates my leaky bladder. My symptoms have markedly decreased since I totally gave up coffee and caffeinated soft drinks. Can I get dementia protection from decaffeinated coffee?

A. At least one study has linked higher-than-average caffeine consumption to a lower risk of dementia (Journals of Gerontology: Series A, Dec. 14, 2016). This was an observational study rather than a controlled clinical trial, though, so we can’t infer a cause-and-effect relationship.

Another epidemiological study found that people in Taiwan were less likely to develop dementia if they ate fish and vegetables or drank tea or coffee (Journal of Prevention of Alzheimer’s Disease, 2017).

Laboratory research suggests that other ingredients in coffee besides caffeine also may be protective (Neurobiology of Aging, October 2016). Quercetin, a compound that appears to be neuroprotective, is found in apples, onions, capers, tea and red wine, as well as coffee. It also might appear in decaf.

Q. I have suffered with nocturnal leg cramps for many years. Long ago, my doctor prescribed quinine pills, and they did the trick. No more cramps.

Then the Food and Drug Administration, in its wisdom, banned the sale of quinine. After much pain, I discovered that tonic water contains quinine. Every evening, I have a large glass of tonic water, and I have no more cramps!

A. Doctors used to prescribe 200-300 mg of quinine for nighttime leg cramps. A glass of tonic water would provide about 20 mg, one-tenth of the dose.

We suspect that the bitter taste of the quinine in tonic water may stimulate special receptors in the mouth, throat and stomach. Even a small amount might be sufficient to stop leg cramps quickly.