We recently discussed vitamins and their role in supporting the body’s various metabolic processes. These are classified “micronutrients” are necessary components to basic functions, but are also required in the optimal balance to achieve overall health and wellness. Clients may often inquire about supplementation and whether taking vitamins are necessary. A healthy and balanced diet usually requires all one needs to obtain essential vitamins, but only an in-depth vitamin analysis could reveal deficiencies and even toxically high levels of a particular vitamin.
Recall that there are two types of vitamins, water-soluble and fat soluble.
Water-soluble vitamins dissolve in water and are absorbed in the GI tract and are not readily stored (like fat-soluble vitamins), are utilized quickly, and need to be replenished more frequently as a result. Vitamins C and the B complex are water-soluble. Toxicity is unlikely since these vitamins are excreted quickly and not stored.
Fat-soluble vitamins such as A, D, E, and K are mostly absorbed passively in the GI tract by binding to dietary fats and are also stored in the body’s fatty tissues making toxicity possible if an individual ingests too high a dose of one of these vitamins.
Consequences of Deficiencies and Overconsumption
Although vitamin needs, intake, and absorption will vary for each fitness client, there are some signs that will point to a deficiency or level of toxicity that requires attention and a referral to the appropriate health professionals. Here’s a simple breakdown – consider this your “cheat sheet” for a quick vitamin overview.
|Fat-soluble Vitamin||Food Sources||Functions||Deficiency Examples||Toxicity Examples|
|A (carotenoids)||Red, orange, yellow fruits & veggies||Synthesizing proteins, immunity, red blood cell development||Dry eyes, acne; rough, dry skin; difficulty seeing in low light||Nausea, headache, fatigue, dizziness, birth defects during pregnancy|
|Fish, mushrooms, egg yolks, fortified dairy products||Cell differentiation, immunity, serum calcium levels, regulating glucose tolerance||Rickets in children, low bone density in adults tooth decay||Elevated blood calcium, loss of appetite, nausea, itching, calcification of soft tissues|
This family includes eight antioxidants
|Nuts, seeds, peanuts, dark leafy greens, avocado||Scavenging free radical, expression of immune and inflammatory cells||Muscle weakness, damage to red blood cells, impaired vision, acne||Impaired blood clotting|
(phylloquinone) – Plant-based
(menaquinone) – Animal-based
|Leafy greens, asparagus, cruciferous greens, cheese, egg yolks, beef, dairy, chicken, duck, goose liver, grass-fed butter||Blood clotting (both), amino acid metabolism co-factor (K2), cell signaling in bone tissue (K2||Bruising, anemia, calcium going to the wrong places||Negating anti-clotting effects from blood-thinning drugs|
|Water Soluble Vitamin||Examples of Sources||Function in Body||Signs of Deficiency||Signs of Toxicity|
|Vitamin B1 (thiamin)||Beans, legumes, whole grains||Producing energy, synthesizing DNA/RNA||Beriberi, Wernicke-Korsakoff syndrome (resulting from chronic deficiency in alcoholics)||None known|
|Vitamin B2 (riboflavin)||Soybeans, mushrooms, eggs, almonds, whole grains, eggs, spinach||Metabolizing drugs and toxins, red blood cell production, iron metabolism||Damage to mucous membranes, loss of appetite, anemia, fatigue, anxiety||Not well absorbed as it is only somewhat water-soluble; none known|
|Vitamin B3 (niacin)||Whole grains, fish, pork, chicken, canned tomato products||DNA repair, maintaining health of skin, digestive system, nerves, influences lipid synthesis in liver||Diarrhea, dementia||Nausea, headache, liver toxicity, insulin resistance, flushing of the skin|
|Vitamin B5 (pantothenic acid)||Mushrooms, corn, peas, potatoes, lentils, egg yolk, poultry, yogurt, seafood||Forming acetyl-CoA, drug metabolism, maintaining skin health||Tingling feet (only in severe malnutrition)||Very rare but could include nausea, heartburn, diarrhe|
|Vitamin B6 (pyridoxine)||Potatoes, sunflower seeds, chickpeas, spinach, fish, beef, poultry||Glycogen breakdown, red blood cell metabolism, nervous and immune function, forms neurotransmitters and steroid hormones||Nervous system disorders, confusion, depression, anxiety||Neurological symptoms – pain|
|Vitamin B7 (biotin)||Nuts, sweet potatoes, onions, whole grains (oats), liver, dairy, fish, pork, legumes||Forming carboxylases, DNA replication and transcription||Dry or rashy skin, nausea, hair loss, conjunctivitis, depress||Unlikely|
|Vitamin B9 (folate)||Beans, legumes, leafy greens, chicken liver||Forming new proteins, breaking down and using B12 and C vitamins, fetal development||Anemia, low white blood cells, weakness and weight loss, low birth weight, and neural tube defects||Masks Vitamin B12 deficiency|
|Vitamin B12 (cobalamin)||Fish and shellfish, beef (liver), dairy||Forming and maintaining healthy nerve cells and red blood cells, DNA synthesis||Neurological problems, loss of appetite, fatigue, depression, megaloblastic anemia, mouth inflammation||Extremely rare|
|Choline (grouped with Vitamin B)||Shellfish, eggs, salmon, pork, chicken, tomato products, legumes||Building cell membranes, liver metabolism, nutrient transport||Problems metabolizing fats, liver and/or kidney disease, muscle and nervous tissue damage, cognitive disruption||Rare without supplementation but can cause hypotension|
|Vitamin C||Most colorful fruits and veggies, organ meats||Protecting cells from free radicals, improves iron absorption, regenerates vitamin E supplies, builds collagen, synthesizing norepinephrine and carnitine, metabolizing cholesterol to bile acids||Poor wound healing, poor dental health||diarrhea, higher risk for kidney stones|
Though these organic compounds do not provide a caloric value and thus give us energy directly, they are both directly and indirectly involved in a number of metabolic processes and physiological functions. They are critical to surviving and thriving. As a fitness professional, you are not qualified to diagnose a deficiency (or toxicity) but you are qualified to review your clients’ macro and micronutrient patterns and observe changes in those patterns that may contribute to an issue later on. Remember, when in doubt, refer out.
Beradi, J., Andres, R., St. Pierre, B., Scott-Dixon, K., Kollias, H., DePutter, C. (2018). The Essentials of Sport and Exercise Nutrition, 3rd Edition.