B12, folate supplements may be key to tackling chronic fatigue

• Chronic fatigue is thought to affect more than 3 million people in the United States alone.
• Experts are unsure what causes it, but it may occur after a viral infection or major physical stressor.
• Now, a study has found that deficiencies in vitamin B12 and folate (vitamin B9) are linked to physical and mental fatigue, so may be a factor in chronic fatigue.
• The researchers suggest that, while their study cannot prove causation, maintaining adequate levels of these B vitamins could help to reduce fatigue-related outcomes.

Fatigue is something that everyone experiences from time to time, but for some people, it is not a transient symptom, but a chronic condition that affects their daily functioning.

Chronic fatigue, the Centers for Disease Control and Prevention (CDC) report, may affect around 3.3 million Americans, interfering with work, school and social life, as well as day-to-day tasks.

Experts believe that chronic fatigue may sometimes follow a viral infection, or could occur after extreme physical stress, such as major surgery. It is 2–4 times more likely to occur in women than men.

A new study from Japan suggests that diet may influence energy levels and motivation. The research, published in Nutrients, found that people who had raised levels of a biomarker, homocysteine, indicating deficiency in vitamins B9 (folate) and B12, were more likely to experience fatigue or lack of motivation than those who had adequate levels.

Although the cross-sectional analysis cannot prove causation, researchers suggest that further studies into links between diet and fatigue should be carried out to verify their findings.

Eamon Laird, PhD, Lecturer in Nutrition ATU Sligo and Adjunct Professor TCD Dublin, Ireland, who was not involved in this research, told Medical News Today that the study raised an interesting hypothesis, and that there seemed to be an association between these B-vitamins and measures of fatigue, but emphasized that the findings should be interpreted with caution.

And Thomas M. Holland, MD, MS, Physician-Scientist and Assistant Professor, Division of Digestive Diseases and Nutrition, Rush Institute for Healthy Aging, Chicago, likewise not involved in the study, commented that:

“One of the most important takeaways from this paper is that homocysteine may serve as a broader biomarker reflecting metabolic stress, vascular health, inflammation, or micronutrient status rather than simply indicating isolated B12 or folate deficiency alone.”

“The findings fit within a larger body of research linking elevated homocysteine with cardiovascular and cognitive outcomes, suggesting that these metabolic pathways may influence multiple aspects of health simultaneously,” Holland added.