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DEAR DR. ROACH: How could I have an A1C of 5.9% in March, then 8% in July? My diet has been the same. I rarely eat fast food and never drink sodas; I avoid carbs such as sweets and breads whenever possible. Because I was so encouraged by my A1C of 5.9%, I increased my vigorous swimming routine to 2 hours a day. I’m cutting this down to 1 hour on most days, since it didn’t do any good.
I do have anemia with hemoglobin and hematocrit at low to low-normal levels, which is always due to AVMs (arteriovenous malformations). I’m 77, and my BMI is over 30. I do need to lose some weight, but this has been a struggle for me for 30 years. I’m thinking of trying GLP-1s, which has been suggested to me by my physician. -- M.R.
ANSWER: The hemoglobin A1C level is a measure of a person’s average blood sugar. Over time, sugar molecules attach themselves to the hemoglobin in red blood cells. With higher levels of sugar, more sugar molecules can be found on hemoglobin.
This high of an increase in an A1C level in such a short time is usually associated with a person who greatly reduced or stopped their diabetes medications. (A level of 8%, if confirmed, is diagnostic of diabetes that isn’t particularly well-controlled.) If a person isn’t on diabetes medicine and hasn’t changed their diet, then physicians should think of a less-common scenario.
True increases in an A1C level can come from damage to the insulin-producing cells with both Type 2 diabetes and latent autoimmune diabetes in adults (a subtype of Type 1 diabetes). Other hormone abnormalities (cortisone, thyroid) and pancreatic disease (inflammation, pancreatic cancer) are rare but worrisome possibilities.
In my opinion, the most likely issue is a false increase in your A1C level, and iron deficiency is the most common one. Your AVMs (direct connections between the arteries and veins that are prone to bleed) could cause an iron-deficiency anemia. Red blood cells with an iron deficiency live longer than average, which provides a longer time for sugar to get attached. A blood count, along with a fructosamine level or a continuous glucose monitor, can evaluate this possibility.
If you have a true increase in your blood sugar, then a GLP-1 agent like semaglutide would be an excellent choice to normalize your blood sugar and help you lose weight, while giving you some heart protection. Of course, there could be a combination of an actual increase in your blood sugar with worsening anemia. But since there weren’t any changes to your diet and exercise before getting the results, it’s most likely to be a false increase.
DEAR DR. ROACH: I’m curious as to what you might know about trimethylaminuria. In particular, how does it affects one’s breath? To my understanding, there’s no cure since it’s an inherited disorder. -- Anon.
ANSWER: Trimethylaminuria usually is an inherited disorder, resulting from a lack of the metabolic enzyme flavin-containing monooxygenase 3, or FMO3. This enzyme converts a malodorous compound triethylamine (TMA, which has a characteristic fishy odor) to an odorless compound (TMAO), which is then excreted in the urine.
TMA is produced by the gut from some dietary precursors (such as eggs and legumes). When a person with low levels of the enzyme has these precursors, their breath, sweat, urine, and other bodily fluids will have the characteristic odor. The odor has nothing to do with hygiene.
Although there isn’t a cure, treatment for the abnormal odor involves limiting the precursor-rich foods; supplemental B2 to help the small amounts of the enzyme that they do have to work better; and antibiotics or charcoal to reduce the bacterial production of TMA.
People with trimethylaminuria should also be cautious with some medications, as the enzyme helps detoxify them. These meds include clozapine, selegiline, ranitidine, tamoxifen and sulindac.
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. (c) 2026 North America Syndicate Inc.
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