Water Soluble Vitamins b9 b12 c 2

The Science of Supplementation: Water Soluble Vitamins, Part 3

April 9, 2018

In this article, I will introduce you to the final three water-soluble vitamins. To recap, water-soluble vitamins dissolve in water and are lost through bodily fluids. Because our body cannot properly store or recycle these water-soluble vitamins, we need to make sure that we consume them in our diet and via supplements. And because our bodies do not store these nutrients, toxicity from too much water-soluble micronutrients is rare.

Folate (B9)

Vitamin B9 is found in three different forms: 1) folate is found naturally in foods, 2) folic acid is the synthetic form that is used in supplements and fortified foods, and 3) L-methylfolate is the form that is active in the body. For the purposes of this article, I will refer to it moving forward as folate.

The word folate comes from the Latin word folium which means “leaf,” as it was originally found in spinach leaves. Similarly, it is found in other dark leafy greens, as well as asparagus, Brussels sprouts, soybeans, beef liver, brewer’s yeast, a variety of beans, salmon, avocado and fortified foods, to name a few.

Like the other B vitamins, folate is used to convert carbohydrates from food into glucose which serves as fuel for the body. Folate is important for brain function, and the production of DNA and RNA, especially during periods of growth such as infancy and pregnancy. It also plays an important role in the metabolism of amino acids (the building blocks of protein).

Folate deficiency is rarely found without other concurrent nutrient deficiencies and is primarily associated with a poor diet. Deficiency is more prominent for people with Celiac’s disease, inflammatory bowel disease and/or excessive alcohol intake. It can lead to anemia, as folate is required in the formation of blood cells. Other symptoms of deficiency include glossitis (inflamed tongue), decreased appetite, diarrhea, irritability, and forgetfulness.

Folic acid is often found in increased doses in prenatal vitamins in order to prevent neural tube defects in the growing infant while the mother is pregnant.

The tolerable upper intake level (UL) has been established at 1,000mcg/day. Folate that occurs naturally in food sources has not been associated with adverse effects. However, very high doses (greater than the UL) of the folic acid form, while rare, can cause issues with sleep, nausea, lack of appetite, skin reactions and confusion. High doses of folate/folic acid (great than 1mg/day) can also mask a vitamin B12 deficiency and potentially worsen the symptoms of vitamin B12 deficiency. If you are currently undergoing treatment for cancer or seizures, please talk to your doctor before taking folic acid supplements.

Folate deficiency may occur in up to 65% of patients after WLS, making supplementation very important.

The ASMBS Guidelines suggest 400-800mcg daily from a multivitamin or B complex vitamin, and 800-1,000mcg daily for women of childbearing age. If you are found to be deficient in folate, it is recommended to supplement 1,000mcg daily until normal levels are reached, and then resume the 400-800mcg daily supplementation.

Vitamin B12

Vitamin B12, also known as cobalamin because of its cobalt content, is often thought of as the energy vitamin. Like the other B vitamins, it is a coenzyme essential for converting food into fuel for the body. It works closely in tandem with folate to form red blood cells and assist in iron function. Folate and B12 also work to help form SAMe, an important component in regulating mood and immune function. Unlike other water-soluble vitamins, B12 can be stored in our liver and recycled in our body for many years; however, this does not mean that deficiency is impossible.

B12 is found only in animal products (meat, dairy, seafood, eggs), with a few rare exceptions such as tempeh and nori seaweed, which contain only small amounts of B12. Specific foods rich in B12 include sardines, beef liver, salmon, feta cheese, cottage cheese and eggs.

When we aren't getting enough B12, it may take time for a deficiency to develop. Due to its ability to be recycled (the duration of recycling can vary from person to person), by the time the deficiency occurs and symptoms develop, you've likely not been getting enough B12 for a prolonged time. Scientists learned this by studying vegans/vegetarians, who would have great B12 stores for years until all of a sudden they were deficient, which the researchers found was due to the lack of B12 food sources (i.e. animal products) in the vegan/vegetarian diet.

The risk of B12 deficiency is increased in the elderly, as our stomachs produce less stomach acid and intrinsic factor as we age. Intrinsic factor (IF) is produced by the parietal cells of the stomach and is required for the absorption of B12 in the ileum (final part of the small intestines). The fundus (upper curve of the stomach) is the primary location of parietal cells. As the fundus is mostly removed in patients with sleeve gastrectomy, this increases the likelihood of decreased IF production.

Water Soluble Vitamins

Symptoms of B12 deficiency include fatigue, sore tongue, numbness/tingling, decreased appetite, nervousness, and diarrhea, and severe cases of deficiency can lead to permanent nerve damage. When severe, B12 deficiency can develop into pernicious anemia, which includes the same symptoms of B12 deficiency, as well as weakness, pale skin, weight loss, fever, loss of balance, confusion, mood changes and even memory loss (dementia). If not treated, some of the neurological damages from B12 deficiency can become permanent.

B12 deficiency has been shown to occur in up to 20% of patients after WLS, and with the risk of possible permanent damage, supplementation is important. The ASMBS Guidelines suggested supplementation for all WLS patients is shown in the table below. No tolerable upper intake level (UL) has been established, as no adverse effects have been found for high intake. There are four types of B12: cyanocobalamin, hydroxocobalamin, adenosylcobalamin, and methylcobalamin. Most supplements (including B12 injections) are cyanocobalamin due to its stability, but the most commonly occurring form of B12 in foods is hydroxocobalamin. Some research suggests methylcobalamin might be better absorbed via injection than cyanocobalamin, but further research is needed.

Oral: Disintegrating,
Sublingual or Liquid
Nasal Spray Intramuscular
or Subcutaneous
350-500 mcg daily As directed by manufacturer 1,000 mcg monthly

Vitamin C

Vitamin C is also known as ascorbic acid. The only non-B vitamin in the water-soluble category, vitamin C is often thought of as the “immune boosting” vitamin, and unlike the B vitamins, vitamin C is not a coenzyme. It is an antioxidant that helps fight off oxidative stress from free radicals that contribute to aging (think wrinkles), affect cardiovascular health, and can even lead to cancer. Vitamin C also strengthens the immune system and plays an important role in collagen synthesis. Collagen plays an important part in the health of your skin, bones (including your teeth!), blood vessels, and tendons/ligaments. In addition, vitamin C aids in the absorption of nonheme iron (stay tuned for the article on minerals for more info!).

Vitamin C is primarily found in fruits and vegetables. However, the vitamin C content in foods can be depleted by cooking/drying, so eating your fruits and vegetables only slightly cooked or raw will help you get the most vitamin C. The best sources of vitamin C include all citrus fruits (especially oranges and grapefruit), tropical fruits (papaya, pineapple), green peppers, tomatoes, cauliflower, and broccoli. Animal products, when cooked, typically contain almost no vitamin C, but raw fish, liver, and eggs can still contain small amounts.

People who smoke are at an increased risk of vitamin C deficiency, as well as those who have a history of stroke, cancer, high blood pressure, alcoholism, gallbladder disease and/or atherosclerosis (plaque buildup in the blood vessels). While vitamin C may not cure or prevent these conditions, a diet high in fruits and vegetables may help reduce your risk of developing these conditions.

One thing to note is that taking vitamin C at the onset of a cold has not been shown to reduce the duration/severity of the cold, but regularly taking vitamin C can help reduce the duration by about one day.

Early symptoms of deficiency include fatigue/weakness. As deficiency advances, it can lead to scurvy, a disease characterized by connective tissue breakdown. Scurvy symptoms include inflamed/bleeding gums, spotted skin, loss of teeth, dry eyes, impaired wound healing, and joint pain. If not treated, scurvy can be fatal. An interesting anecdote: throughout history, scurvy primarily occurred in sailors on long voyages. In 1747, James Lind discovered that lemons and oranges could treat and prevent scurvy, but it still took nearly 50 years for lemon juice to become a requirement for naval voyages of the British Navy. (Fun fact of nutrition!)

High amounts of vitamin C (greater than 2-3g daily) are typically tolerated well, but can sometimes cause stomach issues such as cramps, nausea, gas, and diarrhea. As our bodies can only absorb a certain amount of vitamin C at one time, any excess vitamin C that your body doesn’t use is excreted. Because of this, toxicity is very rare. However, for some people predisposed to kidney stones, high doses of vitamin C (greater than 1g daily) can increase the risk of kidney stones. No tolerable upper intake level (UL) has been established.

As vitamin C can be found in such a variety of foods, we are often able to get adequate amounts from diet alone. Therefore, there are no established guidelines for supplementation for vitamin C after WLS.

Water Soluble Vitamins Summary

As micronutrients at risk for deficiency after WLS, folate and vitamin B12 both have established supplementation values from ASMBS. Folate is particularly important in women of childbearing age if there is a chance they may become pregnant, in order to prevent neural tube defects. Vitamin B12 is important for energy metabolism and neurological function. Vitamin C is an important antioxidant that helps maintain our immune system and connective tissues, and it is so widely available that supplementation is typically not needed.

Of note, all of the B vitamins work synergistically in their functions as coenzymes in many metabolic pathways.

It is important not to supplement just one of the B vitamins for a prolonged period of time (unless correcting a deficiency) in order to avoid creating an imbalance. That is why B vitamins are often sold as a B complex multivitamin.

These are just three of the water-soluble micronutrients. Be sure to check out the previous articles in this series on the other water-soluble vitamins, and please stay tuned for my next article, which will be looking at the fat-soluble vitamins!


UL: tolerable upper intake level, DRI: dietary reference intake, AGB: adjustable gastric band, SG: sleeve gastrectomy, RYGB: Roux-en-Y gastric bypass




Bec McDorman, MS, RDN discovered her passion for health and wellness after undergoing Roux-en-Y Gastric Bypass surgery in 2010 to lose more than 100lbs. Bec has received her masters from Cal Poly Pomona and completed her dietetic internship at Johns Hopkins Bayview Medical Center. She has reached her goal of being a registered dietitian so she can help pre- and post-op bariatric patients with their journey.

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