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Medical drug against type 2 diabetes is a frequent cause of vitamin B12 deficiency

- which may lead to serious physical and mental diseases

Medical drug against type 2 diabetes is a frequent cause of vitamin B12 deficiencyRecent studies reveal that around 20% of people who take metformin, a drug against type 2 diabetes, are vitamin B12 deficient (or borderline deficient). Lack of vitamin B12 may cause anemia, increased risk of osteoporosis, and symptoms of the nervous system that may be confused with ageing processes. It even looks as if lifestyle changes may have a more positive effect on blood sugar management.

Type 2 diabetes is spreading like a bushfire, and a growing number people affected by the disease use a drug called metformin. Common side effects of this drug are reduced appetite, diarrhea, nausea, abdominal pain, and taste disorders. Metformin taken for several years may increase the risk of a vitamin B12 deficiency, which must be compensated for by means of a supplement of the nutrient.

Vitamin B12 has many essential functions

Vitamin B12 is important for cellular energy metabolism, and it supports folic acid in the production of red blood cells. Vitamin B12 converts homocysteine to methionine and S-adenosylmethionine (SAMe), which is involved in the immune system, nerve impulses, and our mental balance. Vitamin B12 contributes to the formation of the myelin sheaths that protect and isolate our nerves, kind of like the plastic coating on electric wires.

What are the symptoms of a vitamin B12 deficiency?

It normally takes years for a vitamin B12 deficiency to develop, and the symptoms are often difficult to detect if a person merely feels tired or uncomfortable, or there are other problems involved. The things to be particularly aware of include:

  • Anemia and accompanying fatigue, palpitations, chest pain, or other symptoms caused by a lack of oxygen in the cells
  • Poor memory, mental fatigue, dementia, and muscle weakness that is often associated with ageing processes that are not properly addressed with relevant treatment
  • Pernicious anemia caused by a lack of the protein intrinsic factor, which is responsible for the uptake of vitamin B12
  • Increased risk of osteoporosis and Alzheimer's disease

Vitamin B12 and bones

A recent study has demonstrated that older women with low levels of vitamin B12 are exposed to more rapid loss of bone mass in their hips, which is a clear sign of osteoporosis. A meta-analysis has even shown that older people may reduce their risk of bone fractures by increasing their levels of vitamin B12.
Vitamin B12 reduces the risk of Alzheimer's disease and other neurological disorders
Another known feature of vitamin B12 is its influence on the nervous system. According to a small, Finnish study that is published in the journal Neurology, people who consume a diet that is rich in vitamin B12 are less likely to develop Alzheimer's disease when they grow older.

Metformin and lack of vitamin B12

Researchers at the Albert Einstein College of Medicine in New York have analyzed different sources of data to determine how metformin therapy affects levels of vitamin B12. The data was collected from people who had either taken metformin or placebo every day for a long period. Vitamin B12 levels in both groups were measured after five and 13 years, and the researchers found that the people in the metformin group had significantly lower levels of the nutrient. Around 20% of those in the metformin group were vitamin B12 deficient (or borderline deficient). Also, there were more people in the metformin group who had anemia, which is associated with vitamin B12 deficiency.
The patient information that is enclosed with metformin preparations encourages people to have their levels of vitamin B12 measured every other year. The above mentioned study supports this. It would also be ideal to combine metformin with supplements of vitamin B12 to prevent deficiencies. Nonetheless, the study reveals that vitamin B12 deficiencies among metformin users are common.

Sources of vitamin B12 and other causes of deficiencies

Although we humans are able to synthesize vitamin B12 in a healthy intestinal flora, our primary sources of this nutrient are normally meat, fish, eggs, and dairy products. This means that vegetarians and vegans are at risk of a deficiency.
It is generally more difficult to take up vitamin B12 from our food and from supplements, and our ability to absorb the nutrient decreases with factors like age weak stomach acid. In addition, overconsumption of alcohol, impaired ability to store the nutrient in the liver, plus estrogen, birth control pills, sleeping pills, and long-term use of several other medical drugs may affect our vitamin B12 uptake.

Lack of vitamin B12 is widespread

According to the Framingham Heart Study, nine percent of the general American population lacks vitamin B12, while 16 percent of the population is borderline-deficient. It is commonly said that vitamin B12 deficiencies are most common among the older people because they have difficulty with producing enough gastric juice and because they take medicine. However, according to the Framingham Heart Study there were many younger individuals with deficiencies.

Blood samples and diagnosis

A vitamin B12 deficiency is detectable through a blood test. Low vitamin B12 is often seen in connection with lack of folic acid and elevated homocysteine.

Supplements and injections

It takes sufficient stomach acid to be able to utilize vitamin B12 supplements properly. Supplements should normally be taken together with supplements of folic acid and other B vitamins that work in synergy with vitamin B12. Moreover, supplements should be taken separately from antacids and other acid-neutralizing substances like natron. In some cases of pernicious anemia, vitamin B12 should be given as injections.

Metformin versus lifestyle changes in diabetes

The scientists who discovered that metformin is a common cause of vitamin B12 deficiency, collected data from a study called the Diabetes Prevention Program. This study showed that simple lifestyle changes were more effective than metformin in terms of preventing or managing diabetes symptoms. The three-year study revealed that those who had had engaged in 15 minutes of daily moderate exercise reduced their risk of developing diabetes by 58% compared with the control group. In comparison, those who took metformin only had a 31 percent lower risk of developing the disease.
It is widely accepted that an unhealthy diet, lack of exercise, and a large waist circumference increases the risk of type-2 diabetes, and it often doesn't take all that much to produce detectable improvements of the blood sugar and health in general


Vanita R Aroda et al. Long-Term Metformin Use and Vitamin B12 Deficiency in the Diabetes Prevention Program Outcomes Study. Endocrine Society 2016

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