Glucophage and B12

Submitted by Dana on Tue, 2010-07-13 15:30

Ah, yes. Another day, another reason diabetics should rely on a low carb diet instead of on ever-increasing doses of hypoglycemic medication.

Turns out that metformin, aka Glucophage, can cause malabsorption of vitamin B 12, and can therefore lead to B 12 deficiency. Since Glucophage is one of the most commonly prescribed diabetes medications, especially in obese diabetics, this potentially affects thousands, maybe millions, of people.

What are the potential symptoms of B12 deficiency? Many of them are actually symptoms of pernicious anemia that results from B12 deficiency: fatigue, poor memory and concentration, irritability and depression. Sleep difficulties may happen, too. So our hypothetical diabetic is now a candidate for antidepressants and sleeping pills.

There can be digestive problems, too, including nausea and heartburn. Reach for the antacids, or even the proton-pump inhibitors.

Nerve damage can set in if it goes far enough, including irreversible nerve cell death. Numbness and tingling in the extremities, lack of coordination, distorted proprioception (sense of where the body is located in space), all are possible. Since nerve damage is a recognized complication of diabetes, I find myself wondering how one distinguishes between diabetic nerve damage and nerve damage caused by B12 deficiency.

All of this takes quite a while to happen -- months or even years. If people swallowed their first dose of metformin and the next day had all these symptoms, the cause would be clear. But with this sort of gradual onset, and with symptoms that can so easily be attributed to other causes, or even to the diabetes itself, I worry that the possibility of B12 deficiency may be overlooked.

Of course, a low carbohydrate not only helps control blood sugar, but also supplies ample quantities of B12, since the best dietary sources are liver, shellfish, beef, some fin fishes, and eggs. How many of these foods are limited on the standard, ADA-backed low fat and cholesterol "diabetic diet?" This can create a double-whammy: A B12-poor diet, coupled with medication that limits absorption of the vitamin.

I don't meant to suggest that metformin has no legitimate uses. In The Atkins Diabetes Revolution, Dr. Mary Vernon says that metformin is the only hypoglycemic medication she prescribes, because it is the only one that doesn't have weight gain among its side effects. However, Dr. Vernon first puts patients on a low carbohydrate diet; only if blood sugar levels are still too high that she prescribes the drug, and of course with tight carbohydrate restriction doses can be kept to a minimum. This will have the effect of increasing intake of B12 while lessening the chance that the drug will prevent the body's using it.

It just frustrates the life out of me how one intervention leads to another and another, and in the case of diabetics, it all starts to spiral out of control when they are put on a low fat, low cholesterol diet, instead of restricting the macronutrient they cannot metabolize, and the one macronutrient for which there is no dietary requirement.

Insanity.

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Diabetes Medicines and B-12 deficiencies

Submitted by dianelyon on Mon, 2010-07-19 12:38.

Hello,
I am having all these symptoms that you are talking about. I take way too much medicine and insulin. I am also taking the antidepressants that you are talking about and I have high blood pressure. You have enlightened me. I'm going to ask the doctor to check my B-12. I am constantly tired, have lots of trouble with memory loss, am already showing signs of nerve damage in a couple of my toes, I'm always sick to my stomach, and various other symptoms. Since I've started low-carb eating AGAIN, my sugar counts have gone down to the normal range, but the doctor still will not take me off any medicines.
I believe that all this medicine is also inhibiting my weight loss. I've only lost 12 lbs. since the middle of May and I can't seem to budge in the last 3 weeks. I eat veggies, proteins, some nuts, very little fruit, very little Truvia, and an occasional low carb Russell Stover chocolate.
It's so discouraging, but I know that low carb is the best way to eat. I've been on and off for years. I always come back to low carb because I seem to be more satisfied with what I'm eating. I can't even begin to tell you how many other diets I've tried. Thank You, Thank You, Thank You for your books, blogs and research. Diane

Diabetes, PCOS and Metformin

Submitted by nanaimo12 on Sun, 2010-07-18 17:43.

Certainly, a low-carb diet is the optimal manner to treat high blood sugars / high blood insulin. However, metformin is also a front-line medication for women with polycystic ovary syndrome. PCOS is an insulin-linked disorder that can (and often does) lead to diabetes, but it has other health implications arising from the higher-than-normal male hormones and the lack of progesterone. One of these is a significantly greater risk of uterine cancer. For that alone, metformin treatment is worth the inherent risks. The adverse impact PCOS has on fertility can also be ameliorated with metformin. In fact, one of my co-workers was only able to conceive normally after taking metformin for a year (with the end result being a healthy, happy girl).

It is good to know that B12 absorption is affected by metformin, so that this malabsorption can be countered by supplementation. Perhaps it is a "side effect" of one of its primary methods of operation - inhibiting uptake of glucose from the intestines (with results like that of eating too much sugar alcohols). Nevertheless, even when taking into account the downsides of the "diarrhea pill", metformin is definitely one of the better medications available for those of us with PCOS, especially people like me who also have diabetes (and I say this as someone who HATES taking pills!). Metformin assists the low-carb diet by making weight loss easier, allowing for the subsequent reduction in the medication as the insulin sensitivity increases.

::stepping off the soap box:: LOL

As a long time glucophage

Submitted by dlmoak on Wed, 2010-07-14 10:52.

As a long time glucophage user and 25-year diabetic, I read the reports on B12 deficiency with interest a couple of weeks ago. I eat a very low carb diet, but at present, the only way I can maintain normal blood sugars, as opposed to just very well controlled blood sugars, is to also use metformin (the glucophage generic).

One can test for B12 levels annually to detect problems with levels and address them. I may be able to maintain normal blood sugars without metformin at some point in the future, but that is not an option for all type 2 diabetics. I agree that the basis of treatment and the first line of attack is a very low carb diet.

I enjoy your blog!