Malnutrition Definition, Symptoms, Causes and Treatment - Dr. Axe

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Malnutrition: 10 Most Common Nutrient Deficiencies & How to Overcome Them


Malnutrition - Dr. Axe

Malnutrition is a serious issue that affects millions around the globe. The standard American diet can lead to malnutrition too. Believe it or not, you don’t have to have protruding bones or gaunt features to be considered malnourished. In fact, many people who suffer from malnutrition can appear perfectly healthy and may not even notice any symptoms at all.

So what is malnutrition, and what’s the best way to prevent it? Keep reading to find out what you need to know about this global epidemic and whether or not you may be affected.

What Is Malnutrition?

The term “malnutrition” may bring about mental images of starvation, extreme hunger or severe weight loss. However, there are many different ways to define malnutrition. It can even occur in people who may appear otherwise healthy.

So what is malnutrition? The official malnutrition definition translates to “poor nutrition,” which can be caused by a lack of any of the nutrients that your body needs, including calories, protein, essential fatty acids, vitamins or minerals. However, few people realize that malnutrition may also be caused by an excess of certain nutrients in the diet, an issue that can often be just as detrimental to health.

Generally speaking, there are two main types of malnutrition, including:

  • Protein-energy malnutrition: caused by either a lack of protein or a lack of protein and calories.
  • Micronutrient deficiency diseases: characterized by a deficiency in specific vitamins and minerals, such as iron, calcium, iodine, vitamin D, etc.

There are a number of potential causes of malnutrition. Some of the most common malnutrition causes include a poorly planned diet, poverty, loss of appetite or digestive disorders that interfere with nutrient absorption. Older adults or people with restrictive diets, eating disorders, reduced intake and increased nutritional needs due to other medical conditions like cancer or kidney disease are all at an increased risk of being malnourished.

So how do you know if you’re getting enough of the nutrients that your body needs? Although there are many hallmark signs of malnutrition and specific vitamin deficiency symptoms, oftentimes the effects of malnutrition go unnoticed for years. For a quick and convenient option, there are plenty of nutrient deficiency test services offered by labs and medical practices that can help pinpoint exactly which vitamins and minerals you lack. Alternatively, you can also work with a registered dietitian to analyze your diet and determine how you can safely meet your dietary needs to stay well-nourished.

Related: What Exactly Does It Mean to Be Immunocompromised?

Top 10 Most Common Nutrient Deficiencies

  1. Vitamin D
  2. Iron
  3. Calcium
  4. Iodine
  5. Magnesium
  6. Vitamin A
  7. Vitamin B12
  8. Vitamin E
  9. Choline
  10. Omega-3 Fatty Acids

1. Vitamin D

Also known as the sunshine vitamin, vitamin D is an important vitamin that is synthesized in the skin in response to sun exposure. Found in very few dietary sources, it can be incredibly difficult to meet your daily needs without stepping in the sunlight. For this reason, vitamin D is sometimes considered the most common nutrient deficiency in the world. Some studies estimating that nearly 42 percent of the U.S. population may have a vitamin D deficiency. (1) Older adults, people with dark skin, those who are overweight or obese, and those with limited sun exposure are at an even higher risk of deficiency.

Symptoms of this vitamin deficiency are often very subtle and may surface only after several years. Vitamin D deficiency has been linked to osteoporosis, bone loss and an increased risk of fractures. (2) It may also result in impaired immune function and increased susceptibility to infections. (3) Because vitamin D is found in few food sources, most people can benefit from supplementation with vitamin D3 to help meet their needs.

2. Iron

Iron is one of the main components of red blood cells. It is crucial in the transportation of oxygen from the bloodstream to the cells. It’s found in two main forms in the diet: heme iron and non-heme iron. Heme iron is more well-absorbed. It is found primarily in meat and animal products. Non-heme iron, on the other hand, is found in a variety of plant and animal sources but is not nearly as bioavailable. Because of this, vegans and vegetarians are at an especially high risk of iron deficiency.

According to a survey conducted by the World Health Organization, nearly 25 percent of the global population is deficient in this essential nutrient. That equates to over 1.6 billion people around the world. (4) Iron deficiency anemia is the most common side effect of low iron levels. This can cause anemia symptoms like fatigue, shortness of breath, brittle nails and pale skin. Iron deficiency can be corrected through either diet modifications, supplementation or a combination of both to ensure that needs are met.

3. Calcium

Calcium is absolutely vital to several aspects of health, from bone metabolism to nerve signaling. (5) Found primarily in dairy products, soft-boned fish and leafy greens, many people don’t get nearly enough calcium in their diets. In fact, one study published in the Journal of Nutrition even found that less than 10 percent of teenage girls and women over 50 met the daily recommended intake for calcium. (6)

A deficiency can be absolutely detrimental, resulting in a range of calcium deficiency symptoms. These include cramps, muscle weakness, low energy levels and muscle spasms. Even more serious side effects can also occur over time, such as osteoporosis and rickets, a condition characterized by the softening of the bones in children. (7, 8) Calcium deficiency is often treated using both diet and supplementation, although the potential effects of calcium supplements has been a subject of controversy in recent years.

4. Iodine

Iodine is an important mineral that plays a central role in thyroid function and the production of thyroid hormones. These hormones help regulate everything from metabolism to body temperature, brain development and beyond. (9) For this reason, getting enough iodine in your diet is key to keeping your thyroid working efficiently and preventing thyroid problems.

Iodine deficiency can cause goiter, which is an enlargement of the thyroid gland. It may also cause other symptoms, such as fatigue, increased sensitivity to cold, an impaired ability to focus, constipation and weight gain. (10) Fortunately, iodine deficiency can usually be avoided by including plenty of iodine-rich foods in the diet, including seaweed, wild-caught cod, yogurt, eggs, tuna fish and iodized salt.

5. Magnesium

Magnesium is a mineral that acts as a co-factor in nearly 300 enzymatic reactions in the body. It also forms the structure of the bones and teeth, supports healthy nerve and muscle function, and aids in the regulation of blood sugar levels. (11) Unfortunately, most of us are sorely lacking in this essential mineral. One study out of Hawaii estimates that nearly half of all U.S. adults consume less than the recommended daily value. (12)

Some of the most common signs of deficiency can include loss of appetite, nausea, weakness, vomiting and fatigue. (13) Taking a multivitamin or including plenty of magnesium-rich foods in your diet, such as nuts, seeds, legumes and leafy greens, can sidestep a magnesium deficiency and help round out your diet.

Malnutrition - Dr. Axe

6. Vitamin A

This fat-soluble vitamin is perhaps most well-known for its effects on eye health. It’s also involved in many other physiological processes, including skin cell turnover, immune function and reproductive health. (14) Although vitamin A deficiency is uncommon in many parts of the world, it’s a serious problem in many developing countries. Some reports estimate that up to 127 million preschool-aged children and 7 million pregnant women around the world may lack this key vitamin. (15)

Vitamin A deficiency symptoms include frequent infections, dry eyes, night blindness and dry skin. Consuming plenty of vitamin A foods can combat deficiency, including organ meats, carrots, squash, leafy green vegetables and sweet potatoes.

7. Vitamin B12

Involved in blood cell formation, energy production, nerve cell function and DNA synthesis, there’s no doubt that your body needs a steady stream of vitamin B12 to function efficiently. However, because it’s found mostly in animal products, such as meat, fish and poultry, vegetarians and vegans are at an alarmingly high risk of deficiency. In fact, some reports estimate that the deficiency rates for these at-risk populations could reach up to 86 percent. (16)

Megaloblastic anemia is the most common side effect of vitamin B12 deficiency. This is a condition characterized by a low number of red blood cells. Aside from increasing your intake of vitamin B12 foods, supplementation is the best bet to reduce your risk of deficiency. Many multivitamins contain vitamin B12, or you can opt for a B-complex to get a concentrated dose of all of the B vitamins that your body needs in one shot.

8. Vitamin E

Vitamin E doubles as both a fat-soluble vitamin and powerful antioxidant. It helps fight free radicals and protects the cells against free radical damage. (17) Because the average Western diet is typically high in processed junk and low in nutrient-rich whole foods like fruits and veggies, many people struggle to meet the daily recommended intake for vitamin E.

Deficiency is rare but can occur in those with impaired fat absorption or certain digestive disorders. Symptoms often include weakened immunity, difficulty walking, loss of vision or loss of muscle control. Wheat germ, nuts, seeds and veggies are a few of the most concentrated sources for this vital vitamin. It can also be found in some multivitamins and is available in special water-soluble forms for those with absorption issues.

9. Choline

Choline is an essential nutrient that is necessary for metabolism, neurotransmitter synthesis, the formation of cell membranes and brain development. (18) It is found in many food sources but is especially prevalent in animal products, such as eggs, meat and dairy. Although it is also found in several plant-based sources as well, it’s a nutrient that should be monitored closely if you’re on a restrictive diet to make sure you get enough.

A lack of choline has been associated with liver and muscle damage, as well as birth defects and impairments in growth and development. (19) Deficiency is typically treated through the diet. Supplements are also available and sometimes used for more severe cases.

10. Omega-3 Fatty Acids

Omega-3 fatty acids are heart-healthy fats that have been linked to decreased inflammation, enhanced cognitive function and improved heart health. (20) The most active forms, DHA and EPA, are found primarily in fatty fish like salmon, sardines and anchovies. Omega-3 fatty acids can also be obtained from some plant sources in the form of alpha-linolenic acid (ALA) as well, but studies estimate that only about 5 percent is actually converted to the active forms in the body, putting those who don’t eat fish regularly at an increased risk of deficiency. (21)

Omega-3 fatty acid deficiency can result in symptoms like difficulty concentrating, joint pain, mood swings, dry skin and brittle nails. For those who don’t eat at least two servings of fatty fish per week, omega-3 supplements are widely available in the form of fish oil, cod liver oil, krill oil and algal oil.

Complications and Disease Related to Malnutrition

Nutritional deficiencies contribute to a long list of diseases and disorders. They can cause many negative malnutrition symptoms and health complications as well. Here are a few of the most common malnutrition diseases that can be caused by a lack of one or more specific nutrients in the diet:

  • Iron-deficiency anemia
  • Osteoporosis
  • Hypothyroidism
  • Megaloblastic anemia
  • Goiter
  • Scurvy
  • Rickets
  • Beriberi
  • Pellagra
  • Protein energy malnutrition (also known as protein calorie malnutrition)
  • Xerophthalmia

How to Avoid Nutrient Deficiencies

The safest and most effective malnutrition treatment is simply making a few swaps in your diet to ensure you get all of the nutrients that your body needs. For most people, following a diet rich in nutrient-dense foods, like fruits, veggies, protein foods and healthy fats, is all it takes to meet your nutritional needs. A multivitamin can also be a beneficial and simple way to round out your diet and help fill in the gaps

Supplementation can also aid in the prevention of malnutrition. In fact, it may be necessary for some people, including those who are on restrictive diets or suffer from digestive disorders that impair nutrient absorption. In this case, it may be best to work with a trusted health care practitioner to determine the best way to meet your micronutrient needs and what dietary changes are necessary for you.

Meal Plan to Overcome Deficiencies

Following a clean eating meal plan is one of the easiest ways to squeeze in all of the nutrients that you need. Here is an example of a one-week meal plan full of healthy ingredients and whole foods to help you optimize your diet and prevent malnutrition. Keep in mind that you may need to make modifications based on your specific needs and to account for any underlying health conditions or other factors.


  • Breakfast: Oatmeal with berries, cinnamon and raw honey
  • Snack: Garlic roasted chickpeas
  • Lunch: Buddha Bowl with flank steak and cashew sauce
  • Snack: Sliced apples with almond butter
  • Dinner: Grilled salmon with asparagus and potato wedges


  • Breakfast: Sweet Potato Hash topped with eggs and roasted veggies
  • Snack: Flax crackers with hummus
  • Lunch: Baked chicken breast with quinoa, cooked carrots and steamed spinach
  • Snack: Carrots and celery sticks with guacamole
  • Dinner: Butternut Squash Ravioli with mushrooms and arugula salad


  • Breakfast: Overnight oats with fruit salad
  • Snack: Probiotic yogurt topped with walnuts
  • Lunch: Slow Cooker Chicken Gumbo with brown rice and side salad
  • Snack: Strawberries and dark chocolate
  • Dinner: Bell peppers stuffed with ground beef and roasted veggies


  • Breakfast: Vegetarian Egg Casserole
  • Snack: Veggies with pico de gallo dipping sauce
  • Lunch: Zucchini noodles with anchovies, garlic and olive oil
  • Snack: Air-popped popcorn
  • Dinner: Steak Fajitas with riced cauliflower and kale


  • Breakfast: Scrambled tempeh and veggies
  • Snack: Seed crackers with tzatziki
  • Lunch: Bone Broth Protein Meatball Soup with side salad
  • Snack: Chia pudding topped with fresh fruit
  • Dinner: Chicken pot pie with lentil soup


  • Breakfast: Chocolate Banana Protein Pancakes
  • Snack: Trail mix with nuts, seeds and dried fruit
  • Lunch: Black bean veggie burger with avocado, tomato, lettuce and sweet potato wedges
  • Snack: Zucchini chips
  • Dinner: Zesty Turkey Salad with beans and walnuts


  • Breakfast: Hard-boiled eggs with sliced avocado and sprouted bread
  • Snack: Banana with almond butter
  • Lunch: Eggplant Flatbread Pizza with Caesar salad
  • Snack: Baked cinnamon apple chips
  • Dinner: Grilled chicken, veggie and hummus wrap with sautéed broccoli

Stats and Facts

Malnutrition is often dismissed as a problem that only affects developing countries. However, while it’s true that certain areas are more prone to malnourishment and specific nutrient deficiencies, malnutrition is a global issue that can affect anyone.

Here are some quick facts and statistics on malnutrition around the globe:

  • The official nutritional deficiency definition can include a lack of any specific nutrient, including calories, proteins, fats, vitamins or minerals.
  • In developing countries, deficiencies in iron, iodine, vitamin A and zinc are most common. (22)
  • Although it’s unclear what is the single most common nutrient deficiency in the U.S., many adults lack vitamin D, iron and vitamin B12. (23)
  • Meanwhile, vegetarians and vegans are at a higher risk of deficiency in nutrients like iron, vitamin B12, zinc, calcium and omega-3 fatty acids.
  • Iodine deficiency is considered the most preventable cause of mental impairment worldwide. (24)
  • Some research shows that climate change may contribute to changes in the nutritional value of plants. This could potentially contribute to nutritional deficiencies in some areas. (25)
  • Malnutrition in children is one of the most serious risk factors for illness and death. It is associated with 52.5 percent of all deaths in young children. (26)


While today we know just how much of a role nutrition plays in overall health, that hasn’t always been the case. In fact, researchers have only learned about the connection between vitamin and mineral consumption and conditions caused by nutritional deficiencies, such as scurvy and beriberi, within the last several hundred years.

From the 1940s onward, many food manufacturers began fortifying products with several essential vitamins and minerals as a public health measure to help prevent nutritional deficiencies. Flour was fortified with a myriad of B vitamins, breakfast cereals began being enriched with vitamin D and iodized salt started being stocked on the shelves of every supermarket. This was highly successful at eradicating many common nutritional deficiencies. It also helped decrease the risk of birth defects and serious conditions like rickets in children in many countries.

Unfortunately, malnutrition remains one of the biggest health problems around the world. This is especially true for pregnant women and young children, who are at a greater risk of deficiency. Initiatives have been set forth by organizations like the United Nations and the World Health Organization in an attempt to address world hunger, as well as related factors like poverty, improved nutrition education, sustainable agriculture and food security. (27)

Risks and Side Effects

Malnutrition can be a serious problem that goes beyond what you put on your plate. If you suspect you may have a nutritional deficiency, consult with a doctor or dietitian to determine what other factors may be at play, as well as the best course of treatment for you.

Additionally, keep in mind that not all nutritional deficiencies can be cured by simply switching up your diet. In some cases, severe deficiencies may require supplementation, sometimes using high doses or injections performed under medical supervision. In any case, talk to your doctor before starting supplementation, especially if you’re taking other medications or have any underlying health conditions.

Final Thoughts

  • The official malnutrition definition translates to “poor nutrition” and is characterized by insufficient nutrient consumption, including an inadequate intake of calories, protein, essential fatty acids, vitamins or minerals.
  • Some of the most common nutrient deficiencies include iron, calcium, vitamin D, vitamin B12, choline, vitamin E, omega-3 fatty acids, magnesium, iodine and vitamin A.
  • In many cases, micronutrient deficiencies can be corrected by following a healthy, well-rounded diet or using a multivitamin to help fill in any gaps.
  • In some cases, other factors may be involved and supplementation or medical treatment may also be necessary.
  • For most people, however, following a balanced diet rich in fruits, veggies, protein foods and healthy fats can ensure that your dietary needs are being met to help prevent malnutrition and nutritional deficiencies.

Read Next: 11 Largest Nutrition Lies in the Media

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