Fasting During Menstruation is Safe for Healthy Women of Reproductive Age
For healthy women of reproductive age, fasting during menstruation is safe and may even provide beneficial effects on menstrual symptoms, cardiovascular function, and stress response.
Evidence Supporting Safety
The available evidence demonstrates that short-term fasting during menstruation does not pose health risks for healthy women and may offer therapeutic benefits:
Cardiovascular benefits: A randomized crossover study found that 12-hour fasting during both follicular and luteal phases resulted in increased parasympathetic activity (higher heart rate variability) and decreased heart rate, indicating a favorable cardiovascular response 1.
Stress reduction: The same study showed decreased salivary cortisol concentrations during fasting in the luteal phase, suggesting an anti-stress effect that may help reduce menstrual symptoms 1.
Symptom improvement: A randomized controlled trial of therapeutic fasting (≤500 kcal/day for 10 days) demonstrated significant reductions in menstrual pain, cramps, nausea/vomiting, dizziness, and mood changes, with effects persisting through multiple menstrual cycles 2.
Quality of life enhancement: The same trial showed significant improvements in both physical and psychological quality of life measures, along with reduced absenteeism during menstruation 2.
Physiological Considerations
Women's bodies adapt well to fasting during menstruation under normal circumstances:
The cardiovascular and autonomic nervous system responses to fasting remain stable across menstrual phases, with no adverse effects observed in healthy young women 1.
Time-restricted eating (TRE) appears to be a feasible lifestyle intervention for women of reproductive age, though the long-term impacts require further study 3.
Important Caveats and Contraindications
Fasting is NOT recommended for certain high-risk populations:
Women with diabetes (pre-existing or gestational) should be strongly advised against fasting due to high risk of maternal and fetal complications, ketosis, and metabolic derangements 4.
Pregnant women should avoid fasting, particularly those with diabetes, as it carries high risk of morbidity and mortality to both fetus and mother 4.
Women with eating disorders, significant nutritional deficiencies, or other metabolic conditions should be evaluated individually before considering fasting.
Nutritional Awareness for Menstruating Women
Women of reproductive age who choose to fast should be aware of their increased iron requirements:
Menstruating women require an additional 50-100 mg elemental iron daily compared to non-menstruating individuals 5.
Iron absorption can be enhanced by consuming iron supplements alongside citrus fruits/drinks or vitamin C, and iron should be taken 1-2 hours apart from calcium supplements 5.
Women should be educated about the importance of dietary enhancers and inhibitors of iron absorption, particularly when following plant-forward diets 5.
Clinical Bottom Line
For the healthy, non-pregnant woman of reproductive age without diabetes or other metabolic disorders, fasting during menstruation is safe and may provide symptom relief and improved quality of life. However, attention must be paid to adequate iron intake given the increased requirements during menstruation, and high-risk populations should be counseled against fasting.