The Science of Supplementation: Fat-Soluble Vitamins, Part 2

August 3, 2018

In the Fat-Soluble Vitamins, Part 1 article, I introduced you to vitamin D, which plays an important role in bone health and is especially important after WLS, as well as vitamin A, which helps support skin and eye health. In this article, I will discuss the remaining fat-soluble Vitamins E and K. Remember that these fat-soluble vitamins can be stored in the fat in our body, and require small amounts of fat for better absorption into our body.

Vitamin E

Vitamin E is a powerful antioxidant that works to protect cells from damage by free radicals, specifically when fat goes through oxidation. It also helps support our immune system, healing and blood circulation. Niacin, selenium and vitamin C help to enhance vitamin E’s antioxidant properties.

Vitamin E is broken into two groups: tocopherols and tocotrienols. In each of these two types are additional forms of alpha, beta, gamma, and delta. The most common circulating type of vitamin E is alpha-tocopherol.

Good sources of the alpha-tocopherol form of vitamin E include nuts, seeds, avocado, olives, and vegetable oils. Most of our dietary intake of vitamin E is found in the form of gamma-tocopherol, found in foods such as peanut butter, kiwifruit, mango, tomatoes, spinach, and broccoli. It is also found in fortified foods. When consumed with unsaturated fat, the antioxidant properties of vitamin E are boosted, ideally with 2-4IU for each gram of unsaturated fat.

Vitamin E deficiency is associated with an increased risk of bone fractures in the elderly. However, unless deficient, supplementing additional vitamin E has not been shown to have any benefit for bone health. Symptoms of vitamin E deficiency include ataxia (gait disturbances), weakness, poor proprioception, eye paralysis, involuntary eye movement, poor night vision, vibration, and anemia due to the breakdown of red blood cells.

Studies show 2.2-26% of pre-op WLS patients are deficient in vitamin E, but deficiency after WLS is relatively uncommon, with 96% of post-op BPD/DS patients (the most at risk for fat-soluble vitamin deficiency) having normal levels up to four years after surgery. Some research supports up to 22.5% of RYGB patients being deficient.

The tolerable upper intake level (UL) has been established at 1000mg/day or 1500IU/day. In the short term, doses great than 400IU are well tolerated, but long-term supplementation of high doses of vitamin E (>400IU/day) has been linked to adverse effects, including increased risk of prostate cancer and death.

Symptoms of high doses of vitamin E include nausea, diarrhea, and gas. At this time, there is no research to support adverse effects from consuming high amounts of vitamin E in food. Most bariatric multivitamins have 60-150IU of vitamin E.

Vitamin E also helps boost the action of the anticoagulant, warfarin, so it is contraindicated to take both at the same time due to the increased risk of bleeding.

The dietary reference intake (DRI) is set as a recommended dietary allowance (RDA) of 15mg/day for adults. Most supplements provide alpha-tocopherol, often in the synthetic form; as the synthetic form (often labeled “DL” or “dl”) is less active, we need about 50% more of it compared to the natural form (often labeled “D” or “d”). If not deficient in vitamin E, it is suggested to take no more than 150mg as part of a multivitamin for the general population.

The new 2016 ASMBS Guidelines recommend 15 mg (22-33IU depending on the form of vitamin E) for all post-operative WLS patients. As vitamin E is commonly listed in both milligrams (mg) and international units (IU), I have provided a conversion table below.

Vitamin K

While most of the other vitamins are named alphabetically in the order of discovery (A, B, C, D, E), vitamin K was named after koagulation, the German word for coagulation, due to vitamin K’s important role in blood clotting, and its discovery in Germany.

Vitamin K’s primary function in our body is to help our blood clot and prevent us from bleeding to death. It also works to support bone and cardiovascular health. Excess vitamin D intake can contribute to arterial calcification (hardening of the blood vessels), but vitamin K works to reduce this buildup.

Phylloquinone (vitamin K1) is primarily found in plant-based foods and is the main source of vitamin K in our diet. Menaquinone (vitamin K2) is found in animal-based foods, as well as fermented soy products, and can also be produced in our large intestines by certain gut bacteria as a byproduct of digestion. Vitamin K has three additional synthetic forms: menadione (vitamin K3), menadiol diacetate (vitamin K4) and vitamin K5.

Vitamin K1 is primarily found in green leafy vegetables, such as parsley, kale, collard greens, spinach, and Brussels sprouts, while vitamin K2 is found in trace amounts in animal-based foods that are high in fat, such as liver, butter, and egg yolk, while it is found in higher amounts in natto, a fermented soy product.

While vitamins A and D can be stored in the body, vitamin K is not typically stored in substantial amounts. Because of this, a diet poor in vitamin K can lead to a deficiency within as little as a week. Those who experience fat malabsorption, such as RYGB and BPD/DS patients, are particularly at risk for vitamin K deficiency. Other at risk include those with Celiac disease, IBD and/or cystic fibrosis.

Other medications and vitamins can also influence the absorption of vitamin K, including broad-spectrum antibiotics and high doses of vitamins A, while large doses of vitamin E have actually been shown to counteract vitamin K’s effect on blood clotting. Despite all of this, actual vitamin K deficiency is rare.

The primary symptom of vitamin K deficiency is excessive bleeding, but low levels have also been linked to higher risk of bone fractures due to poor bone density (osteoporosis), specifically in women. Other symptoms include bleeding gums (a common symptom of vitamin C deficiency), bruising easily, and heavy bleeding during menstruation or nosebleeds.

There is no available data on pre-op deficiency for WLS patients. It is believed to be uncommon both before and after surgery except for BPD/DS patients, for whom deficiency is common after a year.

There is currently no UL established for vitamin K due to the low potential for toxicity, as it is not readily stored in the body due to rapid metabolism and excretion. The established RDI helps support blood coagulation, but vitamin K has been shown to have additional cardiovascular and bone health benefits at higher levels. High intake of one of the synthetic forms, vitamin K3, has been linked to some adverse effects, but as no symptoms have yet been identified for vitamin K toxicity, further research is needed.

Vitamin K is incredibly important for those who are on anti-coagulation therapy, specifically those who are taking warfarin (common brands include Coumadin and Jantoven), which is a blood thinner that is used to help prevent blood clots. While sources of vitamin K do not need to be avoided while on anti-coagulation therapy, it is very important to maintain a consistent intake of sources of vitamin K on a day to day basis.

This will help your doctors analyze your INR, a lab value that assesses the duration of time that it takes for your blood to clot. If you consume too much vitamin K, your INR may rise above the therapeutic range that your doctors wish you to have. If you don’t consume enough vitamin K while on anti-coagulation therapy, you are at risk for bleeding out if you experience even a minor cut. Your doctors will be able to assess your INR and adjust your dosage based on your day-to-day dietary habits, so maintaining a consistent intake is very important.

The RDI established for vitamin K is the adequate intake (AI), which is supported by weaker evidence that the RDA (the amount established that is needed to meet the needs of at least 97.5% of the population). Additional side effects of supplementation of the natural form of vitamin K include reducing the risk of bone fractures, improving the survival of liver cancer patients, reducing the risk of heart disease, and in high amounts, potentially leading to insulin resistance for older men; overall, more research is needed for both the benefits and risks of moderate to high amounts of long-term vitamin K supplementation.

See the table below for the comparison of the AI and the recommendations for the various WLS types.

Fat-Soluble Vitamins Summary

As micronutrients at risk for deficiency after WLS, vitamins E and K both have established supplementation values from ASMBS. Recall that vitamin E is a powerful antioxidant that works to remove free radicals from our bodies, while vitamin K is important for blood clotting and helps with bone health. Of note, water-miscible forms of fat-soluble vitamins are available to help improve absorption, especially for BPD/DS post-op patients.

These are just two of the fat-soluble vitamins. Be sure to check out my series of articles on digestion and vitamin supplementation. Please stay tuned for my next article, which will be looking at important minerals after WLS!

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Terms

• UL: tolerable upper intake level
• DRI: dietary reference intake
• AGB: adjustable gastric band
• SG: sleeve gastrectomy
• RYGB: Roux-en-Y gastric bypass
• BPD/DS: biliopancreatic diversion with duodenal switch

References

https://www.ncbi.nlm.nih.gov/books/NBK56068/table/summarytables.t2/?report=objectonly
https://ods.od.nih.gov/Health_Information/Dietary_Reference_Intakes.aspx
https://asmbs.org/wp/uploads/2008/09/ASMBS-Nutritional-Guidelines-2016-Update.pdf
https://asmbs.org/wp/uploads/2014/05/nutritional-guidelines.pdf
https://www.healthline.com/nutrition/fat-soluble-vitamins
https://examine.com/supplements/vitamin-e/
https://ods.od.nih.gov/factsheets/VitaminE-HealthProfessional/
https://examine.com/supplements/vitamin-k/
https://ods.od.nih.gov/factsheets/VitaminK-HealthProfessional/
https://www.cc.nih.gov/ccc/patient_education/drug_nutrient/coumadin1.pdf

ABOUT THE AUTHOR 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. Read more articles by Bec!

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