Vitamins are organic substances found in small quantities in natural food sources that have many essential functions for human health and are vital components for wellbeing.
Water-soluble vitamins such as Thiamin, Riboflavin, Niacin, Pantothenic Acid and Folic Acid enter the bloodstream easily and are efficiently removed by kidneys from our systems. They help release energy, build proteins and metabolize fat efficiently for greater overall wellbeing.
Vitamin A
Vitamin A is an essential nutrient essential to many bodily processes. It plays a key role in maintaining healthy skin, eyes and immunity as well as cell division and reproduction. You can find Vitamin A both in animal foods such as liver or dairy products as well as plant foods with added fortification of this nutrient.
Plant sources of vitamin A include brightly-colored fruits and vegetables such as carrots, sweet potatoes and pumpkin. Vitamin A can also be found in some breakfast cereals; your body makes its own from provitamin A carotenoids such as beta-carotene. Retinol – another preformed form – is present in meats, fish, eggs and some dairy products and vegetables.
High doses of preformed vitamin A (more than 3,000 mcg daily) may be toxic, and synthetic retinoids used medicinally, including isotretinoin for acne and etretinate for psoriasis treatments, may also be potentially toxic.
Vitamin C
Vitamin C (ascorbic acid) is an essential water-soluble vitamin found in many food sources such as fruits and vegetables as well as processed products. Humans cannot synthesize this vitamin themselves so consuming enough vitamin C through food sources is key.
Vitamin C is an antioxidant nutrient, essential for protecting vital molecules such as proteins, lipids, carbohydrates and nucleic acids (DNA and RNA). Furthermore, it plays an integral role in recycling other antioxidant vitamins like vitamin E.
A large prospective cohort study has indicated that vitamin C intake may be linked with reduced coronary heart disease risk; however, most clinical trials have not demonstrated its efficacy as a supplement. Furthermore, taking additional supplemental vitamin C increases aluminum absorption from antacid medications and can diminish some anticoagulants’ effectiveness.
Vitamin D
Vitamin D promotes calcium absorption and maintains adequate serum levels to enable normal bone formation, prevent rickets in children, and decrease osteoporosis risk in older adults. Furthermore, it plays an integral part in glucose metabolism as well as controlling inflammatory and fibrotic processes.
People can receive enough vitamin D from sunlight and diet from April to September in the UK, or by supplementing all year round for those at risk of not getting enough. D2 (ergocalciferol) and D3 (cholecalciferol), two forms available as supplements, differ only in their side chain length but both increase levels in blood. A large clinical trial (VITAL) randomly assigned 25,871 men and women without cancer at baseline to take either 2,000 IU/day D3 or placebo for an average of 5.3 years – rates did not differ between groups (VITAL).
Vitamin E
Vitamin E has an RDA of 15 mg daily (or 22 international units, IU). It can be found naturally in foods like cereal grains, nuts, vegetables and oils; alpha-tocopherol is the most popular form in supplements and fortified food products; other ester forms of this vitamin exist such as dl-alpha-tocopheryl acetate or succinate may also exist.
Studies and some clinical trials have linked higher intakes of vitamin E with reduced rates of cardiovascular disease, although one recent trial which followed participants for 10 years found no association between routine use of vitamin E supplements and reduced rates of nonfatal heart attacks or deaths [24].
Studies suggest that high doses of antioxidants like vitamin E could increase the risk of prostate cancer and interfere with some blood-thinners such as warfarin (Coumadin).
Vitamin K
Vitamin K is an indispensable nutrient, providing essential support for strong bones and blood, aiding clotting of wounds to facilitate healing, and controlling calcium binding to bone and other tissues. You’ll find this nutrient in green leafy vegetables and as dietary supplements.
Vitamin K (phylloquinone) can be found primarily in plant-based foods and fermented products like sauerkraut. Gut bacteria in the large intestine also produce menaquinones (MK-2 to MK-13), another type of vitamin K.
Studies suggest that higher intakes of phylloquinone may help lower rates of hip fracture and osteoporosis, and improve episodic memory in older adults. Another prospective study of more than 4,800 adults 55 years or older concluded that a higher intake of menaquinone was linked with reduced risks of cardiovascular disease hospitalizations (86). Vitamin K may help protect against atherosclerotic calcification of arteries which could lead to heart attacks or stroke.
