Deficiencies in both iron and vitamin D are major worldwide health concerns, reports the International Journal of Preventive Medicine. Iron and vitamin D may have a relationship as cofactors for each other. Vitamin D is needed to absorb iron; low iron or anemia may indicate a vitamin D deficiency in your body. It's important to watch for signs that indicate you might have low levels of vitamin D or iron and consult your doctor to determine the underlying cause.
Anemia and Vitamin D Deficiency
The dependence synergy between iron and vitamin D may have an important role in anemia. A six-month study, published in the journal Nutrients in 2018 examined the relationship between vitamin D and iron deficiency. Researchers found that 23 percent of female athletes in the study were deficient in iron and were 3 times more likely to also be deficient in vitamin D. The inverse was also true — women deficient in vitamin D were 2.7 times more likely to be deficient in iron.
The journal of Current Opinion in Endocrinology, Diabetes and Obesity also reported findings from a 2015 study that suggests that maintaining adequate vitamin D levels may be important in preventing anemia, particularly in inflammatory types.
Low Iron and Anemia
Your body needs iron, especially the liver, which also processes vitamin D. Iron is an important component of hemoglobin and the transportation of oxygen to all of your body tissue. It is also necessary for synthesis of connective tissue, growth, development and normal cellular functioning.
If you're low in iron, your body may not have enough healthy red blood cells, which could develop into iron-deficiency anemia and lead to serious health problems. Initially, you may have no signs if the anemia is mild or the symptoms may develop slowly. Some of these symptoms, according to the American Society of Hematology, are:
fatigue, weakness, dizziness or lack of energy
headache, especially with activity
chest pain, shortness of breath or rapid heartbeat
problems concentrating or depression
tinnitus or "whooshing" in the ears
As the anemia gets worse, symptoms may include:
- pale or yellow "sallow" skin
- craving for ice or clay, known as
- sore or smooth tongue
- brittle spoon-shaped fingernails and toenails
- difficulty swallowing
- dark, tar-colored stools or blood in the stool
Risk Factors for Iron Deficiency
Iron deficiency is very common in women and those who eat a diet low in iron, such as vegetarians and vegans. People with the highest risk for developing an iron deficiency are:
- women who are pregnant or breastfeeding
- individuals who have undergone major surgery or physical trauma
- people with a gastrointestinal disease, such as Crohn's or celiac disease
- people with a stomach ulcer or other cause of bleeding
Sources of Iron From Food
Only a small amount of iron from the food you eat is absorbed and stored in your liver to be used to make new red blood cells in bone marrow. Dietary Guidelines for Americans recommends a daily iron intake of 8 milligrams for adult men and women over the age of 51 and 18 milligrams for women between the ages of 19 and 50. Meat, poultry and fish provide the richest sources of iron and are the type most easily absorbed in your body.
For vegetarians, many plant-based foods contain iron, including legumes; grain products; some fruits, such as apricots and prunes; vegetables, such as spinach and tomatoes; and fortified foods, such as cereal and pasta. Including a source of vitamin C, such as citrus fruits, broccoli, strawberries, tomatoes and peppers, can help with iron absorption.
Symptoms of Low Vitamin D
Vitamin D provides a wide range of functions and is essential for many aspects of health. It plays a role in bone health, hormone regulation, inflammation reduction and muscle and nervous system maintenance. You may have no initial symptoms of low vitamin D, but with prolonged deficiency, symptoms of vitamin D deficiency may include:
- bone pain or easily fractured bones
- muscle cramps
- increased perspiration
- spine deformities or stooped posture and a loss of height
- poor growth in children
- weakness or tingling
Severely inadequate vitamin D stores can lead to complications such as rickets or other serious medical conditions. Vitamin D deficiency may be related to heart diseases, cancer, infant mortality, diabetes, mood disorders and increased risk of infections, according to the report in a study published by the International Journal of Preventive Medicine.
Sources of Vitamin D
Dietary Guidelines recommends you get 600 IU of vitamin D daily. Sun exposure is the best source of vitamin D. The amount of vitamin D synthesized through your skin depends largely on skin pigmentation. If you have fair skin, your body can produce 10,000 to 25,000 IU of vitamin D in as little as 30 minutes depending on the time of day and geographic location, says the Vitamin D Council. Foods that contain vitamin D include beef liver; fatty fish, such as tuna and salmon; cheese; egg yolks; and fortified foods, such as cereals, milk, orange juice and yogurt, according to NIH.
- MedlinePlus: Iron Deficiency Anemia
- American Society of Hematology: Iron-Deficiency Anemia
- Office of Women's Health: Iron-Deficiency Anemia
- Dietary Guidelines 2015-2020: Nutritional Goals for Age-Sex Groups Based on Dietary Reference Intakes and Dietary Guidelines Recommendations
- Dietitians of Canada: Food Sources of Iron
- International Journal of Preventive Medicine: Effects of Iron on Vitamin D Metabolism
- Anemia Central: What's the Connection Between Vitamin D and Iron Deficiency?
- Vitamin D Council: How Do We Know How Much Vitamin D You Make?
- NIH Office of Dietary Supplements: Vitamin D
- Healthgrades: Vitamin D Deficiency: Symptoms
- Nutrients: The Association Between Iron and Vitamin D Status in Female Elite Athletes
- Current Opinion in Endocrinology, Diabetes and Obesity: Vitamin D and Anemia: Insights into an Emerging Association