When it comes to overall health, eating a well-rounded diet is one of the most important things you can do, since it boosts energy, promotes a healthy weight, and reduces the risk of chronic disease. Additionally, it provides your body with a proper balance of macro and micronutrients that are necessary for various metabolic processes [ 1
However, despite your best dietary efforts, it is possible to develop a deficiency in any vitamin or mineral. Some micronutrient deficiencies are more common than others and can develop over time with few noticeable symptoms, making them harder to be detected. So, which nutrients are the most common to be deficient in, and how do you know if you have a deficiency? Let’s dive in and discuss the five most common nutrients people tend to fall short on, what problems they can create, and how to ensure you are getting enough of each.
Disclaimer: If you suspect that you may be deficient in any vitamin or mineral, you should talk to your healthcare provider and have bloodwork done. This offers valuable insight into your health and gives your healthcare provider enough information for proper nutritional care through diet and/or supplement recommendations.
Often referred to as the “sunshine vitamin”, vitamin D is a fat-soluble vitamin that can be synthesized by your skin from exposure to UVB rays [ 2 4
2]. It also has many important functions, such as reducing inflammation, supporting cell growth, improving neuromuscular and immune function, and glucose metabolism. Additionally, it’s known for improving bone health, as it helps the gut absorb calcium to promote bone strength and growth [
Despite vitamin D’s importance, it is estimated that 42% of the general population is deficient [ 4 3
4], and 90% of Elo members start with low vitamin D. This is likely due to the fact that you only obtain vitamin D from a few foods and direct sunshine exposure. Since factors like the season, length of the day, weather, smog, skin melanin content, and sunscreen use affect vitamin D synthesis, your levels could be negatively affected [
Inadequate intake of vitamin D can lead to thin, brittle bones and diseases like rickets and osteoporosis [ 3 9 11 12
3]. Moreover, vitamin D deficiency has been linked to an increased risk of infections (including COVID-19), higher rates of autoimmune disease, and elevated glycosylated hemoglobin (HbA1c), a marker of insulin resistance [
The Recommended Dietary Allowance (RDA) for people between the ages of 1 and 70 is 600 IU/day, and for adults over 70, the RDA is 800 IU/day [ 9
9]. However, depending on your level of regular sun exposure, you may need to obtain more vitamin D from your diet than this.
Vitamin D can be obtained through diet either as either D2 (ergocalciferol) or D3 (cholecalciferol). Vitamin D2 is present in yeast and plants (such as mushrooms) as well as fortified foods, such as milk, breakfast cereals, orange juice, yogurt, and margarine [ 3 3
3]. Vitamin D3, the more effective form for raising vitamin D levels, is naturally present in animal sources (such as oily fish, beef liver, egg yolks, cheese, and fish liver oils), as well as most vitamin D supplements [
Learn more about how to optimize your vitamin D levels
Recent research shows that vitamin D supplementation can be used at 5,000 IU/day (and up to 10,000 IU/day) without any adverse effects . When taking a vitamin D supplement, it’s recommended to take it with a fat source (such as avocado, nuts, and seeds, olive oil, or full-fat dairy products) to enhance absorption [ 13 14 15 16
14]. Some studies also suggest that consuming adequate amounts of magnesium is essential for activating vitamin D, so supplementing with magnesium may be helpful if your levels are low [
To determine whether you need a vitamin D supplement and to figure out the proper dosage, consult your healthcare provider.
Vitamin B12 is a water-soluble vitamin that is necessary for the development, myelination, function of the central nervous system, red blood cell formation, and DNA synthesis [ 5 18
5]. Deficiency can lead to serious complications such as megaloblastic anemia, low white and red blood cell counts, fatigue, glossitis of the tongue, dementia, weight loss, infertility, and neurological changes [
The RDA of vitamin B12 for older children and adults is 2.4 mcg/day, whereas for pregnant and breastfeeding women the RDA is 2.6 and 2.8 mcg/day, respectively [ 5
Fish, meat, poultry, eggs, dairy, and fortified foods (such as breakfast cereals and nutritional yeast) are excellent sources of vitamin B12 [ 5 17
5]. Since many dietary food sources for vitamin B12 come from animal products, plant-based eaters are at greater risk for B12 deficiency — and in fact, 80% of vegans and vegetarians are deficient in vitamin B12. If you follow a vegan or vegetarian diet, it is recommended to consume fortified foods or supplements to meet your B12 requirements [
True vitamin B12 deficiency is typically treated with vitamin B12 injections to eliminate any barriers to absorption. However, high doses of oral vitamin B12 might also be effective. Oral vitamin B12 can be taken as part of a multivitamin, in a B-complex supplement, or as an individual supplement [ 5 5
5]. The dose of a vitamin B12 supplement is typically anywhere from 100 mcg to 1000 mcg, depending on the level of need [
While you should always consult your healthcare provider for supplement recommendations, vitamin B12 has a low risk for toxicity and does not store excess within the body.
Iron is a mineral that is essential for healthy red blood cells, which transport oxygen throughout your body [ 6 6
6]. Additionally, it’s important for growth, neurological development, cellular function, and the synthesis of certain hormones [
Some symptoms of iron deficiency include weakness, fatigue, gastrointestinal symptoms, impaired cognitive and immune function, poor temperature regulation, and anemia [ 6 6
6]. People who are most at risk for iron deficiency include infants and young children, women with heavy menstrual bleeding, frequent blood donors, and people with cancer, GI disorders, or heart failure [
The RDA for iron varies greatly between men and women, as well as by age. The recommended daily allowance for adults is as follows [ 6
8 mg for men and non menstruating women
18 mg for menstruating women 19-50 years old (15 mg for women 18 years old)
27 mg for pregnant women
9 mg for lactating women 19-50 years old (10 mg if 18 years old)
There are two iron forms that exist within foods: heme and non-heme [ 6 6 6 6
6]. Heme iron comes from meat and seafood sources and is more bioavailable than non-heme iron [
6]. Non-heme iron is found in plant sources (such as spinach, broccoli, beans, and legumes) and iron-fortified foods [
6]. Unfortunately for vegetarians and vegans, the bioavailability from non-heme iron sources is only 5-12% and several compounds found in grains, beans, and cereals can diminish the absorption of non-heme iron even further [
A multivitamin with 18 mg of iron can be useful for mild to moderate iron deficiency, while a more severe iron deficiency may require an iron-specific supplement in a higher dose [ 6 6
6]. For vegetarian women of childbearing age, it is important to supplement with iron as studies show that over 20% of women are deficient [
Iron toxicity is possible from supplementation, so it’s important to be supervised by a healthcare professional. Intake of a supplement with more than 20 mg of iron can lead to unpleasant symptoms such as GI discomfort, constipation, nausea, vomiting, and fainting [
Calcium is the most abundant mineral in the body and is essential for blood vessel contraction and dilation, muscle function, blood clotting, nerve transmission, hormone secretion, as well as creating strong bones and teeth [ 7
When dietary consumption of calcium is lacking, your body takes calcium out of the bone to keep calcium levels stable in other parts of the body. Over time, calcium deficiency can lead to weak bones and osteoporosis; in severe cases, neurological symptoms, congestive heart failure, and seizures may occur [ 7
The RDI of calcium is 1,000 mg/day for adult men aged 19-70 and all women aged 19-50. Higher intakes of 1200 mg/day are recommended for women over 50 and men over 70 [ 7
Calcium can be found naturally in milk, yogurt, and cheese, while other sources include canned fish with bones, certain vegetables (such as kale, broccoli, and bok choy), and fortified foods (such as cereals, fruit juices, and tofu) [ 7 7
7]. Dairy products have a higher absorption rate (30%) than plant sources which contain oxalic acid (5%), therefore plant-based eaters may be lacking in this nutrient [
Evidence shows that less than 22% of men and less than 10% of women meet their recommended calcium intake, so supplementation may be recommended to reach those needs [ 7 7
7]. Calcium supplements typically contain between 200 to 500 mg of calcium and are best absorbed when taken alongside a meal [
7]. However, too much supplementation can possibly cause GI discomfort, so be sure to work closely with your healthcare provider to ensure the proper dosage.
Iodine is an essential mineral that is necessary for the function of the thyroid, protein synthesis, enzyme activity, and metabolic function [ 8
Unfortunately, one-third of the world is deficient in iodine, with pregnant women, vegetarians, vegans, and those who live in countries where there is little iodine in the soil at the highest risk. Symptoms of iodine deficiency include hypothyroidism, goiter, unexpected weight gain, fatigue, weakness, hair loss, and/or dry skin [ 8
The RDA for iodine intake is 150 mcg/day in adults, 220 mcg/day in pregnant women, and 290 mcg/day in lactating women [ 8
While iodine is naturally found in some foods such as seaweed, seafood, and eggs, most fruits and vegetables are poor sources of iodine due to soils becoming depleted over the years [ 8
8]. Thus, an easy way to incorporate more iodine within the diet is to use iodized salt when cooking.
Iodine supplements usually contain potassium iodide or sodium iodine, and the dose is usually around 150 mcg [ 8 8
8]. Iodine supplements are absorbed almost immediately by the body, so it’s important to ensure that you are taking the proper dose as recommended by your healthcare provider. Iodine toxicity is possible, and symptoms include nausea, vomiting, and diarrhea [
A well-balanced diet can help ensure that you get adequate amounts of vitamins and minerals throughout the day. However, despite your best dietary efforts, you may still fall short. Vitamin D, vitamin B12, iron, calcium and iodine are some of the most common nutrient deficiencies, but with a balanced diet and supplements, you can increase your levels for optimal health. However, it’s recommended that you work with a healthcare provider to figure out the best nutritional plan for you, especially if it involves supplementation.
Disclaimer: The text, images, videos, and other media on this page are provided for informational purposes only and are not intended to treat, diagnose, or replace personalized medical care.
Despite vitamin D’s health benefits, 42% of the general population is deficient, and 90% of Elo members start with low vitamin D [ 4
Since many dietary food sources for vitamin B12 come from animal products, plant-based eaters are negatively affected, as over 80% of vegans and vegetarians are deficient in vitamin B12.
People who are most at risk for iron deficiency include infants and young children, women with heavy menstrual bleeding, frequent blood donors, and people with cancer, GI disorders, or heart failure [ 6
Evidence shows that less than 22% of men and less than 10% of women meet their recommended calcium intake, so supplementation may be recommended to reach those needs [ 7
One third of the world is deficient in iodine, with pregnant women, vegetarians, vegans, and those who live in countries where there is little iodine in the soil at the highest risk.
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