Water-Soluble vs. Fat-Soluble Vitamins: A Comparison

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    Fat-soluble vitamins should be taken with a high fat food, while water-soluble vitamins are better taken on an empty stomach. It’s all about absorption.

    Vitamins are essential micronutrients that the body needs in small quantities in order to ensure its proper functioning for optimal well-being. These essential nutrients are either not found in the body, or are found in such small quantities that they must be obtained through diet and, when needed, supplementation. Vitamins are categorized as either water-soluble or fat-soluble, depending on how they are absorbed by the body.

    What are Water-Soluble Vitamins?

    Water-soluble vitamins are those vitamins that are dissolved in water and easily absorbed into the bloodstream, making them readily available for use. They are not stored in the body, so any excess amounts are excreted through urine. Because water-soluble vitamins are expelled when not needed, they must be replenished on a regular basis through diet or supplementation. Water-soluble vitamins rarely accumulate to toxic levels, but consuming excess amounts may lead to minor side effects including digestive distress. The category of water-soluble vitamins consists of vitamin C and all of the B vitamins.

    Vitamins A, D, E, and K

    Vitamin A is essential for maintaining healthy vision, ensuring proper functioning of the immune system, and proper fetal growth and development. Some of the best sources of vitamin A are leafy greens, tomatoes, carrots, pumpkins, sweet potatoes, mangoes, beef liver, fish oils, milk, and eggs.

    Vitamin D is necessary in order for the body to absorb calcium and phosphorus, both of which are critical for building bones. More than 40% of Americans have a vitamin D deficiency. The best sources of vitamin D are natural sunshine, fatty fish, beef, cod liver oil, dairy, and fortified foods such as milk, non-dairy milk, orange juice and whole grains. Absorption issues and dietary choices make it difficult to get enough of “the sunshine vitamin” without supplementing. People who eat plant-based diets (vegan and vegetarian diets) may be especially vulnerable to vitamin D deficiency. Care/of has top quality D supplements for those who eat a plant-based diet Vitamin D: The Sunny D3, and for those who eat a vegan diet Vegan D: The Sunny D3.

    Vitamin E is a powerful antioxidant that is important for vision, reproduction, and blood health. Foods that are rich in vitamin E include almonds, peanuts, olive oil, canola oil, leafy greens, and fortified cereals. Most people get adequate amounts of vitamin E from their diet.

    Vitamin K is essential for blood clotting and overall bone health. Some of the best food sources of vitamin K include spinach, kale, blueberries, soybean oil, canola oil, figs, and canned pumpkin. It is fairly easy to get adequate amounts of vitamin K from diet alone.

    What are Fat-Soluble Vitamins?

    Fat-soluble vitamins are those vitamins that are dissolved in fats, absorbed by fat globules, then travel through the small intestines into the bloodstream. Unlike water-solubles, excess amounts of fat-soluble vitamins are stored in the liver and fatty (adipose) tissues for future use. If taken in excess amounts, fat-solubles can accumulate in the body and lead to potential toxic levels. Side-effects depend upon the vitamin but usually range from nausea and vomiting to more serious health challenges. The fat-soluble vitamins include vitamins A, D, E, and K.

    Vitamins B and C

    B vitamins are essential for the proper functioning of the body’s cells. They also help convert food into energy, (metabolism), create new blood cells, maintain healthy brain cells, skin cells, and other body tissues. The best sources of B vitamins include organ meat, beef, fatty fish such as salmon and mackerel, shellfish, milk, cheese, yogurt, and eggs. B vitamins are not naturally found in plant-based foods, but alternative milks (soy, almond, oat, etc.), nutritional yeast, and a number of grains are available fortified with B vitamins. Care/of has an excellent vitamin B complex The Busy B’s and an equally top-notch B12 The Energizer to help with your supplement needs.

    Vitamin C, also known as ascorbic acid, is essential for the growth, development, and repair of all of the body’s tissues. It is also required for the formation of collagen, absorption of heme iron, wound healing, proper functioning of the immune system, and the maintenance of healthy cartilage, bones, and teeth. It is a powerful antioxidant that oxidative stress from free radicals. Some of the best sources of vitamin C are citrus fruit, strawberries, Bell peppers, white potatoes, cruciferous vegetables, and tomatoes. If you are looking to supplement your vitamin C intake, Care/of’s premium Vitamin C The Citrus Savior contains everything you need in your vitamin C.

    How are They Different?

    The main differences between fat-soluble and water-soluble vitamins are how they are absorbed in the body and whether or not they are stored. Water-soluble vitamins are absorbed directly into the bloodstream and, if not used, are excreted through the body’s urine. They can easily be taken on an empty stomach and the likelihood of toxicity is low.

    Fat-soluble vitamins are better absorbed if they are eaten with fat, preferably a meal. They are found in fatty foods and, if not immediately used, stored in the liver and fatty tissues until they are needed. Because they are stored, excess consumption could lead to toxicity. Your doctor can order blood tests to determine your vitamin levels and measure blood levels over time during or after supplementing for a period of time.

    The Bottom Line

    It would be ideal to get all of your essential micronutrients from a diet rich in fresh fruit and vegetables, lean meats, poultry, fatty fish (two servings per week as recommended by the American Heart Association), whole grains, healthy fats, nuts, seeds, yogurt, Greek yogurt, dairy and eggs. This is not always possible, however.

    Supplements are an excellent way to bridge any nutrient gaps you may have. Before you begin your supplementation, it is important to get all of the facts and to consult your healthcare provider for recommendations. If you are pregnant, lactating, trying to become pregnant, have any underlying health conditions, or take any medications on a regular basis, it is especially important for you to talk to your physician before changing your current regimen.

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    Dr. Carla Montrond Correia ND, CNS
    Medical Content Manager
    Dr. Montrond-Correia is a licensed naturopathic physician and a certified nutrition specialist (CNS). She holds degrees from University of Bridgeport, Georgetown University, and University of Saint Joseph, and supplemented her education with internships in the health and wellness space. She's focused on research, herbal medicine, nutrigenomics, and integrative and functional medicine. She makes time for exercise, artistic activities, and enjoying delicious food.
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