Military training and pregnancy increase women’s nutritional needs, specifically for vitamin D, calcium, iron, folate, and iodine. While OPSS always recommends choosing whole foods first, sometimes it can be difficult to get enough of those nutrients through food alone. When nutrient needs are higher than normal or when nutrient-rich foods aren’t available, vitamin and mineral supplements can help women to restore nutrient levels in their bodies. Just remember that you don’t need supplements unless you have known nutrient deficiencies, so talk to your healthcare provider before taking any supplement.

Military training

Intense daily physical training, such as during basic training, increases your calcium and iron needs and has been associated with lower levels of vitamin D in the blood.

Note: In general, service members are not permitted to bring supplements to basic training unless prescribed by a healthcare provider. Regulations regarding supplement use during other types of training may vary by school and service. Contact your Command for specific directions.

Vitamin D and Calcium. Low levels of vitamin D and calcium in the body are associated with weaker bones and increased risk of stress fractures. Studies with female Army and Navy recruits suggest that supplementing diets with calcium and vitamin D during basic training can improve bone health and protect against stress fractures. However, more research is needed to determine if and how much supplemental vitamin D and calcium is effective for preventing stress fractures. Visit the National Institute of Arthritis and Musculoskeletal and Skin Diseases for more information about calcium and vitamin D.

Iron. Women are at increased risk for iron deficiency due to menstrual bleeding. Iron deficiency can affect your performance and make it difficult to complete training. If you can’t get enough iron from food, iron supplements can help. For more information about iron and training, see HPRC’s “Add pep to your training envIRONment.”

Pregnancy and lactation

If you’re pregnant or plan to become pregnant soon, talk with your healthcare provider about taking a multivitamin/mineral (prenatal) supplement that contains folic acid, iron, and iodine. It’s important to get enough folic acid (from food and/or supplements) daily before conceiving to reduce the risk of birth defects. For more information, read the OPSS article about supplements during pregnancy.

Breastfeeding increases certain nutrient needs, such as vitamin A and iodine. However, there’s no consensus on the use of individual or multi-vitamin/mineral supplements during lactation. These vitamins and minerals usually can be obtained by eating a variety of nutrient-rich foods. A healthcare provider can determine individual supplement needs, if necessary, for a breastfeeding mother.  

Note: There is very little research on the safety of herbal or botanical dietary supplement ingredients during pregnancy or lactation, and some may be unsafe. In addition, pregnant and breastfeeding women should be aware of all sources of caffeine in their diet from foods, beverages, supplements, and medications. According to the American College of Obstetricians and Gynecologists, consuming less than 200 mg of caffeine a day during pregnancy and less than 300 mg a day while breastfeeding is safe.


Vitamin and mineral supplements can help female military members meet their nutritional needs during times of increased nutrient use or when unable to meet their needs from foods. However, follow these steps before taking any supplement:

  • Talk to your healthcare provider. Only use supplements if you have known nutrient deficiencies or greater nutrient needs that can’t be met with food alone, and only use them under the supervision of your healthcare provider.
  • Take the recommended dosage. Taking more can cause some nutrients to build up to unsafe amounts in your body.
  • Continue to eat nutrient-rich foods. Although supplements can provide essential nutrients, it’s better to try to get those nutrients from whole foods to optimize performance and overall health. 

Updated 26 February 2019


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