8 Common Nutrient Deficiencies on a Low-Carb Diet

People who go on restrictive diets may not get all of the nutrients that they need. Those who choose low-carb diets—either for weight loss or health management—may not get enough of certain vitamins and minerals including thiamin, folate, vitamin C, magnesium, iron, vitamin D, vitamin E, and calcium.

To make sure that your body functions well on a low-carb diet, consider the sources of each of these micronutrients. Then try to include these foods in your meals and snacks throughout the day so that you get the recommended daily intake of each essential nutrient.

Thiamin

Pecans

Verywell / Alexandra Shytsman

Thiamin (sometimes spelled "thiamine") is important in the body's energy production and brain and nervous system function. Thiamin is also called vitamin B1.

Thiamin works with other B vitamins so that a depletion of one can cause others to function less effectively in the body. This vitamin is also prone to destruction in food processing, storage, and cooking. For this reason, some flour and cereal products are enriched with thiamin.

Recommended Daily Intake

Adult women should consume 1.1 mg and men should consume 1.2 mg of thiamin each day.

Low-Carb Sources of Thiamin

  • Pork loin: Three ounces uncooked provides 0.5 mg thiamin.
  • Macadamia nuts: One ounce provides 0.3 mg thiamin.
  • Chicken livers: Three ounces provides 0.1 mg thiamin.
  • Pecans: One ounce provides 0.2 mg thiamin.
  • Peanuts: One ounce provides about 0.2 mg thiamin.
  • Flaxseed: One tablespoon provides 0.2 mg thiamin.
  • Asparagus: One cup provides 0.2 mg thiamin.

Also, many non-starchy vegetables provide .06 to .09 mg thiamin per cup.

Nutritional yeast or brewer's yeast can also provide thiamin, but read labels and look for a sugar-free variety to maintain your low carb diet. Some brands are fortified with B vitamins so that a teaspoon of nutritional yeast will provide the recommended daily intake. For unfortified yeast, two tablespoons provide about 0.6mg of thiamin. Brewer's yeast provides slightly less.

Folate

Folate is possibly best known for preventing neural tube defects, a type of birth defect. Folate is necessary for many chemical reactions in the body and plays a role in cell formation, especially red cell formation.

Folate is also known as vitamin B9, and it's commonly found in whole foods. Folic acid is found in supplements and fortified foods. Folic acid is more bioavailable—meaning that the body is better able to use it.

Recommended Daily Intake

Adult women and men should consume 400 mcg of folate per day.

Low-Carb Sources of Folate

  • Chicken livers: A 3.5-ounce serving provides 578 mcg folate.
  • Asparagus: One cup provides 70 mcg folate.
  • Spinach: One cup raw provides 58 mcg folate.
  • Brussels sprouts: One-half cup cooked provides 47 mcg folate.
  • Avocado: One half avocado provides 80 mcg folate.
  • Romaine lettuce: One cup provides 64 mcg folate.
  • Broccoli: One cup chopped provides 57 mcg folate.

Also, liver and liver products, salmon, crab, lamb, and most green vegetables are good sources of folate.

Vitamin C

Probably the most well-known vitamin, vitamin C performs many functions in the body. This vitamin is essential for brain neurotransmitters to function properly and it protects our cells from damage. Vitamin C is also necessary for building connective tissue and promotes resistance to infection.

Vitamin C is easily degraded during storage and cooking. To enhance the vitamin C content of your food, keep produce cool and try not to overcook it.

Recommended Daily Intake

Adult women should consume 75 mg and men should consume 90 mg of vitamin C each day.

Low-Carb Sources of Vitamin C

  • Red bell pepper: One half cup raw contains 95 mg vitamin C.
  • Green bell pepper: One half cup raw contains 60 mg vitamin C.
  • Brussels sprouts: One half cup raw contains 48 mg vitamin C.
  • Broccoli: One cup chopped, raw contains 81 mg vitamin C.
  • Strawberries: One cup sliced contains 89 mg vitamin C.
  • Cauliflower: One cup contains 46 mg vitamin C.
  • Grapefruit: One half fruit contains 38 mg vitamin C.
  • Cabbage: One cup, raw, chopped contains 33 mg vitamin C.

Other good sources of vitamin C include kale and other leafy greens, raspberries, green beans, cantaloupe. Almost all fruits and vegetables have some vitamin C.

Magnesium

Magnesium plays a wide role, participating in protein synthesis, bone development and maintenance, DNA synthesis, and cell function.

Many of us don't get enough magnesium. In fact, according to some estimates, 30 percent to 50 percent of Americans don't reach the recommended daily intake.

Unfortunately, people on low-carb diets may fare even worse. In one study, 70 percent of people on the Atkins diet were not getting sufficient magnesium. People on low-carb diets may need magnesium more than others since it is important in glucose metabolism and blood sugar control.

Recommended Daily Intake

Adult women should consume 320 mg and men should consume 400 mg of magnesium each day.

Low-Carb Sources of Magnesium

  • Pumpkin seeds: One cup roasted contains 168 mg magnesium.
  • Spinach: One cup raw contains 24 mg magnesium.
  • Soybeans: One cup raw contains 521 mg magnesium.
  • Almonds: One ounce contains 77 mg magnesium.
  • Peanuts: One ounce contains 48 mg magnesium.
  • Flaxseed: One tablespoon whole seeds contains 40 mg magnesium.

Other good sources of magnesium include legumes, fish, green vegetables, and yogurt.

Iron

Iron is extremely important to our health. Without it, our cells cannot get oxygen. Iron is responsible for hemoglobin formation, improves the quality of our blood, and increases resistance to disease and stress.

And yet, especially for women of childbearing age, iron deficiency is not uncommon. People on low-carb diets tend to eat less of it.

Recommended Daily Intake

Adult women of childbearing age should consume 18 mg of iron each day. Men and women over childbearing age should consume 8 mg of iron each day.

Low-Carb Sources of Iron

  • Chicken liver: Four ounces raw contains 10 mg iron.
  • Beef liver: Four ounces raw contains 5.5 mg iron.
  • Soybeans: One half cup raw contains 15 mg iron.
  • Spinach: One cup raw contains about one milligrams iron.
  • Roast beef: Four ounces contains 4 mg iron.
  • Asparagus: One cup contains just under 3 mg iron.

Vitamin D, Vitamin E, and Calcium

Deficiencies in these nutrients aren't specific to low-carb diets. Many people on a typical American diet don't get enough vitamin D, vitamin E, or calcium.

Vitamin D

Vitamin D is necessary for the maintenance and balance of calcium and phosphorus in the body. This micronutrient also plays a role in other systemic functions in the body.

Getting enough vitamin D can be difficult through food sources alone. Exposure to the sun provides many of us with the amount that we need.

However, vitamin D deficiency is becoming more common. Some believe that it may be due to the fact that people are spending less time outside—especially in winter and in areas far from the equator. In addition, people are also more responsible about wearing sunscreen. 

The recommended intake of vitamin D is 600 IU daily for adult men and women. Low-carb sources of vitamin D include salmon, tuna, eggs, yogurt, and liver.

Vitamin E

Vitamin E is a fat-soluble vitamin that functions as an antioxidant.

There are eight different forms of the nutrient, which is one of the reasons it's best to get vitamin E from foods. Vitamin E supplements usually only contain one or two forms.

The recommended intake of vitamin E is 15 mg daily for adult men and women. Low-carb sources of vitamin E include most nuts and seeds (especially sunflower seeds), greens, avocado, peppers, and shrimp.

Calcium

Calcium plays many roles in the body, but it's best known for the development of bone mass and maintenance of bone strength. It's also vital to the functioning of our muscles and nerves and maintaining the correct acid/base balance.

The recommended intake of calcium is 1000 mg daily for adult men and women. However, women over the age of 51 should consume 1,200 mg per day.

Low-carb sources of calcium include dairy products, sardines, canned salmon, tofu, and dark green vegetables.

Common Questions

Many people following a low carb diet may have questions about vitamin and mineral intake, as well as getting enough micronutrients.

Is it better to get nutrients from supplements or food?

Supplements provide a tempting alternative when you consider the foods you need to eat to get all of these important vitamins and minerals. But they are not always the smartest choice.

Food researchers are finding out there are many many nutrients in foods that we either didn't know about before or that need to work together in the food that we eat.

For example, scientists have discovered tens of thousands of phytonutrients in the plant foods we eat. We are just beginning to understand the complexities of how they interact.

Additionally, supplements may not always provide the amount of nutrient that you need—even if it says so on the label. Food sources provide both micro and macronutrients.

What's the difference between a vitamin or mineral deficiency and not meeting the RDI?

There is a difference between having a diagnosed condition from a nutrient deficiency (such as rickets) and having a low blood level of a nutrient, and not getting the recommended daily intake (RDI) of a given nutrient in your diet.

The information in this article is about meeting your recommended daily intake as defined by the USDA.

Your healthcare provider may give you blood tests and perform other types of exams to make sure your body is getting the nutrients it needs and to perform properly.

If you have other questions about a potential vitamin deficiency on a low-carb diet, speak to your healthcare provider or registered dietitian.

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Article Sources

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  • USDA Dietary Guidelines. Appendix 7. Nutritional Goals for Age-Sex Groups Based on Dietary Reference Intakes and Dietary Guidelines Recommendations

  • USDA Food Composition Database. National Nutrient Database for Standard Reference Legacy Release.

  • Gardner, CD, et. al. "Micronutrient quality of weight-loss diets that focus on macronutrients:results from the A TO Z study".  American Journal of Clinical Nutriion 2010 Aug;92(2):304-12.
  • National Institutes for Health, Office of Dietary Supplements, Fact Sheets (Calcium, Folate, Thiamin, Omega-3 Fats, Magnesium, Vitamin E, Vitamin C, and Vitamin D)