All About Water-Soluble B Complex And C Vitamins

What do you know about water-soluble vitamins? These nutrients aren’t stored by the body, so you need to get enough every day. Most vitamins are actually water-soluble! This includes all B-complex vitamins plus vitamin C.

On the other hand, vitamins A, D, E, and K are fat-soluble, so they’re stored for long periods of time. You don’t need to eat them on the daily, and supplements aren’t usually recommended. It’s a different story with water-soluble vitamins. Since they’re eliminated through the urine, getting enough through the diet is a must. Moreover, B vitamins help metabolize carbohydrates and turn food into fuel, or glucose.1 2

With this guide to water-soluble vitamins, you’ll learn about what they do and where to get them. Water-soluble nutrients include:3

  • Vitamin B1 (thiamine)
  • Vitamin B2 (riboflavin)
  • Vitamin B3 (niacin)
  • Vitamin B5 (pantothenic acid)
  • Vitamin B6 (pyridoxine)
  • Vitamin B7 (biotin)
  • Vitamin B9 (folate)
  • Vitamin B12 (cobalamin)
  • Vitamin C

1. Vitamin B1: Thiamine

Vitamin B1 turns nutrients into usable energy

Thiamine, or thiamin, doubles as a coenzyme. It makes essential processes possible, whether it’s metabolizing carbs or turning nutrients into cell energy. Without thiamine, different cells wouldn’t be able to do their job. Top sources include whole grain foods. White flour isn’t the best bet, as most of the thiamin is lost during processing. You can also get the vitamin from legumes, nuts, lean pork, pecans, and seeds.4


Thiamine deficiency is uncommon in healthy people. However, type 1 and type 2 diabetics tend to excrete more of this nutrient through the urine, causing levels to drop by 75 to 76%. Chronic alcoholism also increases the risk.5 6



thiamine is excreted in the urine, there isn’t a risk of overdose.7

Recommended Dietary Allowance

  • Men, 19 years and older: 1.2 mg
  • Women, 19 years and older: 1.1 mg
  • Women, pregnant or breastfeeding: 1.4 mg

2. Vitamin B2: Riboflavin

Vitamin B2 is a great antioxidant

Aside from turning food into fuel, riboflavin serves as an antioxidant. This means it protects DNA by destroying harmful free radicals. It also supports growth, produces red blood cells, and converts vitamin B6 and folate into usable forms. To get enough riboflavin, eat almonds, organ meats, whole grains, wheat germ, wild rice, soy, broccoli, and Brussels sprouts. These days, flours and cereals are usually fortified with riboflavin.


Deficiency of riboflavin is uncommon. However, elders and alcoholics who eat poor diets are at an increased risk. Low levels are linked to cataracts and migraines.



at high doses, riboflavin is generally considered safe. Overdosing, which is very rare, may cause itching, numbness, prickling sensations, or yellow or orange urine.8

Recommended Dietary Intake

  • Men, 19 years and older: 1.3 mg
  • Women, 19 years and older: 1.1 mg
  • Women, pregnant: 1.4 mg
  • Women, breastfeeding: 1.6 mg

3. Vitamin B3: Niacin

Vitamin B3 is supports digestion

Niacin is the only B vitamin that can be made from tryptophan, the amino acid that reminds people of Thanksgiving. It’s needed to repair DNA, produce energy and support digestion. Even healthy appetite, skin, and nerves depend on niacin.9 10


of this nutrient include tuna, salmon, lean beef, and the light meat of turkey and chicken. You can also get it from fortified cereal, peanuts, lentils, and lima beans, while yeast contains trace amounts.11 12


Niacin deficiency is rare in developed countries, but alcoholism can bring it on. Symptoms of mildly low levels include fatigue, canker sores, vomiting, poor circulation, and depression. Severe deficiency is known as pellagra and causes cracked skin, dementia diarrhea, and a swollen tongue.


High levels cause what’s called a “niacin flush.” This often affects people taking niacin to lower cholesterol, and causes burning, tingling, and flushed skin. Overdose might spark liver damage or stomach ulcers.

Recommended Dietary Allowance

  • Men, 19 years and older: 16 mg
  • Women, 19 years and older: 14 mg
  • Women, pregnant: 18 mg
  • Women, breastfeeding: 17 mg

4. Vitamin B5: Pantothenic Acid

Vitamin B5 is required for every function of the body


acid is present in all foods, plant and animals alike. It’s a precursor to coenzyme A, an essential coenzyme that’s needed for virtually every process in the body. Without enough of this, you wouldn’t be alive! The best sources of pantothenic acid include beef liver, sunflower seeds, trout, yogurt, cooked lobster, and Portobello mushrooms. Gut bacteria can also lend a hand by producing pantothenic acid.


Because this nutrient is everywhere, deficiency is extremely rare.


High intakes may bring on diarrhea, but otherwise, there is no risk of toxicity.13

Recommended Dietary Allowance

  • Adults, 19 years and older: 5 mg
  • Women, pregnant: 6 mg
  • Women, breastfeeding: 7 mg

5. Vitamin B6: Pyridoxine

Vitamin B6 are required to metabolize carbs and fat

In the body, vitamin B6 is converted into pyridoxal 5′-phosphate, or PLP. Both vitamin B6 and PLP are needed to metabolize not only carbs but fat and protein as well. Healthy neurotransmitters and connections also depend on vitamin B6. Salmon is a top source but fortified breakfast cereal, baked potato, turkey, avocado, spinach, and bananas also make the cut.14 15


Children and elders are more likely to have a mild deficiency, but otherwise, it’s rare to be significantly deficient. Some drugs, such as antidepressants called monoamine oxidase inhibitors, may also reduce blood levels.


Extremely high doses of 200 mg or more a day can lead to neurological disorders. Abdominal pain, appetite loss, headache, and sensitivity to light might also crop up.16

Recommended Dietary Allowance

  • Adults, 19 to 50 years: 1.3 mg
  • Men, 51 years and older: 1.7 mg
  • Women, 51 and older: 1.5 mg
  • Women, pregnant: 1.9 mg
  • Women, breastfeeding: 2.0 mg

6. Vitamin B7: Biotin

Vitamin B7 is crucial for nerve health


from metabolism, biotin is crucial for gene expression and nerve health. Many people take this nutrient for strengthening hair and nails, though there’s much research to back up this benefit. Once upon a time, it was also known as vitamin H. Biotin supports the growth of an embryo, making it an essential vitamin for pregnant mothers.
To get enough biotin, eat cooked egg yolk, sardines, almonds, nut butter, soy, legumes, whole grains, bananas, mushrooms, and cauliflower. Brewer’s yeast also provides some of this vitamin.17


Deficiency is super rare in normal, healthy people. Alcoholics and women who are pregnant or breastfeeding are at risk for poor absorption. In some, a rare disorder called biotinidase deficiency stops the body from “recycling” the vitamin.18 If a deficiency develops, symptoms may include hair thinning, rashes, and brittle nails.19


Even at high doses, biotin is considered non-toxic.20

Recommended Dietary Allowance

  • Adults, 19 years and older: 30 mcg
  • Women, pregnant: 30 mcg
  • Women, breastfeeding: 35 mcg

7. Vitamin B9: Folate

Vitamin B9 helps tissue growth

Vitamin B9, which also goes by folate or folic acid, is needed to make DNA, support the brain, and fuel cell and tissue growth. That’s why it’s so important during pregnancy, infancy, and adolescence! This nutrient also teams up with vitamin B12 to produce red blood cells. Rich sources of folate include dark leafy greens, oranges, nuts, beans, poultry, and whole grains. Beef liver also offers a decent amount.2122 23


Unfortunately, low levels are common. Poor absorption may be caused by alcoholism, celiac disease, inflammatory bowel disease, or some medication. Possible symptoms include appetite loss, gingivitis, poor growth, forgetfulness, irritability, and mental fatigue. For a pregnant mother, deficiency can lead to a baby with birth defects of the brain and spine.24


It’s possible to overdose on folate. High levels worsen anemia and cognitive issues, two side effects of B12 deficiency.25

Recommended Dietary Allowance

  • Adults, 19 years and older: 400 mcg DFE
  • Women, pregnant: 600 mcg DFE
  • Women, breastfeeding: 500 mcg DFE

8. Vitamin B12: Cobalamin

Vitamin B12 is key to improving brain function

Vitamin B12 is at the forefront of making red blood cells and DNA. The healthy neurological function also need cobalamin, making it a key nutrient of a healthy brain. Animal foods are the best sources. Clams, beef liver, fish, and fortified cereals come out on top, but dairy products have some B12.26


Vegans have a high risk of deficiency. It can also affect older adults or people with absorption problems, like celiac or Crohn’s disease.27


A high intake of vitamin B12 isn’t known to cause any problems.28

Recommended Dietary Allowance

  • Adults, 19 years and older: 2.4 mcg
  • Women, pregnant: 2.6 mcg
  • Women, breastfeeding: 2.8 mcg

9. Vitamin C

Vitamin C helps increase the immune power of the body

Most people know vitamin C as the ultimate immune-boosting nutrient. It helps white blood cells grow, spread, and kill foreign particles! This vitamin even supports phagocytes, the cells that “eat” bacteria.29 Plus, as an antioxidant, it can find and destroy free radicals. Fuel up on vitamin C with red peppers, oranges, kiwi, broccoli, strawberries, and other fruits and veggies.


Blood levels drop during times of stress.30 Smokers, people exposed to secondhand smoke, alcoholics, and people with malabsorption issues are at risk for deficiency.


High intakes won’t cause serious side effects. Minor symptoms may include diarrhea, nausea and stomach cramps.31 32

Recommended Dietary Allowance

  • Men, 19 years and older: 90 mg
  • Women, 19 years and older: 75 mg
  • Women, pregnant: 85 mg
  • Women, breastfeeding: 120 mg

Everything you need to know about these nutrients is right here.