No meat, no problem? The effect of veganism and vegetarianism on the menstrual cycle

At Clue, we are often asked if vegetarianism and veganism affect the cycle. Is it normal for my period to become longer? Can it affect my fertility? Will my sex drive go down? Will my cramps get better? What about my mood?

The answer is, like most: it depends. “Well-planned” vegetarianism and veganism can be healthy diets at all stages of life (1). Both diets are great options for being more environmentally, morally and health conscious, among other reasons. Many health benefits of vegetarianism and veganism exist, such as decreased risk for diabetes, high cholesterol, cancer, and weight problems (2). All diets have potential risks and benefits, though. Here are a few things to know about your cycle and your diet.

Iron deficiency

Low iron is one of the most common nutritional deficiencies and the source of anemia, especially in women (3). Low iron can result from increased iron losses or inadequate iron intake or absorption (3). Since red meat is some people’s primary source of iron, menstruating women will have to be sure they’re getting enough on a meatless diet. This may become especially true during heavy menstrual bleeding, like after getting a copper IUD.

Low iron can lead to decreased physical and mental performance, weakened immune system, and increased risk of pregnancy complications (3,4).

Most common symptoms of iron deficiency (3):

  • Fatigue
  • Dizziness
  • Headaches
  • Shortness of breath
  • Paleness
  • Flattened, brittle nails
  • Cracks at corners of mouth

If you are worried about low iron, try to stop drinking tea, coffee or milk with or after meals (5). Tannins (in tea) and calcium (in milk) inhibit iron from being absorbed. Instead, increase consumption of vitamin C-rich foods, which enhance iron-absorption. Another option is to take iron supplements (6). Consulting a doctor or nutritionist with any concerns is always a good idea.

Iron-rich foods (3,5):

  • Dark leafy greens
  • Beans and lentils
  • Tofu
  • Grains like quinoa, brown rice and oatmeal
  • Dried fruit
  • Nuts and nut butters
  • Eggs and fish

Shorter periods

Vegetarians have reported shorter periods (4). Low iron may cause shorter periods, and other lifestyle factors may impact period flow. Vegetarians and vegans often have lower BMI and higher rates of physical activity (7). Both low BMI and high amounts of exercise are known to reduce menstrual bleeding if not stop bleeding altogether (8, 9). While irregular cycles are normal, prolonged lack of menstruation may have other impacts on fertility (9). If your period stops for more than three cycles, you should see a doctor (9).

Many people report weight loss on a vegan or vegetarian diet because meat and animal products are often higher in calories, protein and fat (7). If rapid weight loss or restrictive eating results from vegetarianism, your period may also shorten or disappear entirely (8, 9).


Vegetarians are also found to have more menstrual symptoms such as severe premenstrual syndrome (PMS), intense period pain and irregular periods (4). Additionally, vegetarians are suggested to have poorer mental well-being. One study shows that vegetarians ranked significantly higher than non-vegetarians in five categories: difficulty sleeping, depression, panic attacks, deliberate self-harm and back pain (4). Talking about these symptoms with a medical professional will help find a solution, whether you are a vegetarian or not.

Other research shows a possible link between dairy, inflammation and PMS symptoms (10). Dairy contains beta-casein proteins, A1 and A2 casein. A1 casein, the more common protein, can make up 30% of protein found in cow’s milk and is a significant source of inflammation (11). Inflammation is believed to be associated with more severe physical PMS symptoms (10). So vegans and dairy-free vegetarians could experience less severe physical PMS symptoms.

Sex drive

Vegetarians don’t need to worry about decreased sex drive. Studies have shown that vegetarianism does not lower libido but are inconclusive if the diet increases sex steroid levels (12).

Keep tracking

Whether you eat meat or not, your health depends on well-balanced meals. The effect of any diet really depends on the individual. Tracking emotions, sleep, energy and motivation is a great way to start. Also adding tags in Clue will help personalize any symptoms you may have. If you suspect something is wrong, share this information with a medical professional. With their guidance, you can make informed decisions about what, if anything, needs to be changed.

See how diet affects your cycle.


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  2. Hart J. The Health Benefits of a Vegetarian Diet. Alternative and Complementary Therapies. 2009 Apr 1;15(2):64–8.
  3. Alton I. Iron deficiency anemia. In: Stang J, Story M (eds) Guidelines for adolescent nutrition services, 2005.
  4. Baines S, Powers J, Brown WJ. How does the health and well-being of young Australian vegetarian and semi-vegetarian women compare with non-vegetarians?. Public Health Nutrition. 13 Feb 2006. 10(5), 436–442.
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  7. Barr SI. Vegetarianism and menstrual cycle disturbances: is there an association?. The American Journal of Clinical Nutrition. 1999. 70(suppl):549S-54S.
  8. McLean JA, Barr SI. Cognitive dietary restraint is associated with eating behaviors, lifestyle practices, personality characteristics and menstrual irregularity in college women. Appetite. 12 July 2002. 40 (2003) 185–192.
  9. Vale B, Brito S, Paulos L, Moleiro P. Menstruation disorders in adolescents with eating disorder-target body mass index percentiles for their resolution. Einstein (São Paulo). 27 Mar 2014. 12(2):175–80.
  10. Gold EB, Wells C, Rasor MO. The association of inflammation with premenstrual symptoms. Journal of Women’s Health. 2016 May 2.
  11. Pal S, Woodford K, Kukuljan S, Ho S. Milk intolerance, beta-casein and lactose. Nutrients. 2015 Aug 31;7(9):7285–97.
  12. Harmon B, Morimoto Y, Beckford F, Franke AA, Stanczyk FZ, Maskarinec G. Estrogen levels in serum and urine of vegetarian and omnivore premenopausal women. Public Health Nutrition. Sep 2014. 17(9): 2087–2093.