The risk of thiamine deficiency

Severe thiamine deficiency, also known as beriberi, with its array of symptoms such as confusion, tingling and numbness, muscle weakness, unusual eye movements, and heart failure, is virtually unknown in Western societies where most refined grains are enriched with the B vitamins lost during processing. Thiamine and its partner B vitamins are removed through the kidneys, so people who use diuretic medications may be at risk for B vitamin deficiencies that could worsen their health.

Combining diuretics and thiamine

The new study, published in Clinical Research in Cardiology, included nine people with chronic heart failure. All of the participants were being treated with diuretic medications to reduce the fluid build-up in the lungs associated with poor heart function. During the first phase of the study, they were assigned to take either 300 mg of thiamine or placebo each day for four weeks; during the second phase, the assignments were reversed for another four weeks. These phases were separated by six weeks with no thiamine.

Thiamine improves heart function

The researchers found the following:

• Cardiac function improved more in thiamine users than placebo users in both phases of the study. Cardiac function was measured as left ventricular ejection fraction, or the percentage of blood in the left ventricle pumped out of the heart and into the body with each beat.
• There was a small increase after thiamine use, compared to placebo, in performance on a six-minute walking test, which measures the distance people can walk in six minutes.
• Data from 24-hour step counters showed that thiamine use was also associated with more daily walking.
• The differences in cardiac function were statistically significant, but differences in walking ability and daily steps were not, due in part to the small size of the study.

"This study suggests that thiamine supplementation has beneficial effects on cardiac function in patients with diuretic drugs for symptomatic chronic heart failure," the study's authors said. "Subclinical thiamine deficiency is probably an underestimated issue in these outpatients."

Supplements for a failing heart

Before adding supplements to a treatment plan, especially for those with a life-threatening condition, it's important to consult with the treating doctor and to check on the safety of combining supplements with medication. This study suggests that people with heart failure may benefit from taking extra thiamine and most nutrition experts recommend taking a B-complex multivitamin when supplementing with a high dose of any one B. Here are some other supplements to consider:

• Magnesium. Magnesium deficiency is more common in people with heart failure, and this deficiency can lead to irregular heart rhythms. Taking magnesium can help keep the heart rhythm normal. Nutrition specialists generally recommend 300 mg per day.
• Taurine. This amino acid has been found to improve cardiac function by increasing the force and effectiveness of each heart contraction. Doctors typically suggest taking 2 grams, two times per day.
• Coenzyme Q10. Supplementing with 90 to 200 mg of CoQ10 per day has been found to help people with heart failure in some, but not all, studies.

(Clin Res Cardiol 2012;101:159-64)