Ward off diabetes by avoiding processed foods

Dear Dr. Roach: I have been diagnosed with prediabetes (A1c 5.8) and kidney failure (eGFR 58, creatinine 0.97). I am confused about which problem to address through diet. I was advised to eat wheat bread and oatmeal for breakfast, and now I am told that wheat and oatmeal are not good for my kidneys. I understand that white bread, pasta and rice are not good for prediabetes. I do eat a lot of vegetables — asparagus, string beans, escarole — at dinner, but I just don’t know what to do about breakfast. Could you please give me some direction on diet? I don’t want to become a diabetic, and I don’t want to end up on dialysis either. V.C.

The creatinine level is one of the most important ways that physicians evaluate kidney function, and the GFR (glomerular filtration rate) uses the creatinine level to estimate kidney function based on age, sex and weight. An estimated GFR of 58 is moderate kidney dysfunction. At this point, your doctor should have looked at all of your medications to make sure they are at the right dose and warned you about medications that can harm the kidney (like excess doses of Tylenol and anti-inflammatory medications). Protein restriction is controversial, but most experts believe that it is not helpful until the GFR is lower (below 50), and even then has only a modest benefit.

To prevent prediabetes from progressing to diabetes, you’ll want to avoid simple sugars and processed foods, like most white breads, pasta and rice. Whole grains are better, since the fibre slows absorption, and combining carbohydrates with protein and fat amplifies this effect. For breakfast, if you like cereal or oatmeal, you should have whole grain and maybe also have some protein or fat. Animal protein seems to be more likely to worsen kidney function than plant protein.

I strongly advise a visit to a nutritionist for people with severe kidney disease.

Dear Dr. Roach: Is it possible that when immersed in water, you absorb it through your skin? Whenever I spend more than 30 minutes in the pool, I later have to urinate more than when I don’t spend time in the water. Can the absorbed water travel to kidneys? Can the chemicals added to pool water do some damage?

E.M. Water is not absorbed to any appreciable effect when the body is immersed. The reason you urinate more may be due to unnoticed swallowing of pool water, which is very common in swimmers.

Don’t worry about the chlorine in pool water. The amount of chlorine is simi- lar to or only a bit higher than most tap water, and is not enough to be dangerous.

Dear Dr. Roach: You wrote last year about cod liver oil as a source of vitamin D and omega-3. Can you recommend a brand?

M.E.T. I don’t like to recommend specific brands unless there are scientific studies showing a difference between brands, which I can't find with cod liver oil. However, I would look for a brand that is labeled “certified USP,” meaning it is tested for contaminants, and one that has a low vitamin A level (below 10,000 IU daily).

You also might want one with high (450 mg or greater) EPA plus DPA (the most commonly recommended omega-3 fats).