NUTRIENT FACT: Vitamins
Vitamins and minerals are essential substances that our bodies need to develop and function normally. They are micronutrients required by the body to carry out a range of normal functions. However, these micronutrients are not produced in our bodies and must be derived from the food we eat.
Every day, the body produces skin, muscle, and bone. It churns out rich red blood that carries nutrients and oxygen to remote outposts, and it sends nerve signals skipping along thousands of miles of brain and body pathways. It also formulates chemical messengers that shuttle from one organ to another, issuing the instructions that help sustain your life.
But to do all this, your body requires some raw materials. These include at least 30 vitamins, minerals, and dietary components that your body needs but cannot manufacture on its own in sufficient amounts. Eating a healthy diet remains the best way to get sufficient amounts of the vitamins you need.
Vitamins are organic substances that are generally classified as either fat soluble or water soluble. Fat-soluble vitamins (vitamin A, vitamin D, vitamin E, and vitamin K) dissolve in fat and tend to accumulate in the body. Water-soluble vitamins (vitamin C and the B-complex vitamins, such as vitamin B6, vitamin B12, and folate) must dissolve in water before they can be absorbed by the body, and therefore cannot be stored. Any water-soluble vitamins unused by the body are primarily lost through urine.
Now that we are done with introductions, let’s look at the various types of vitamins and uses in the body.
Fat Soluble Vitamins
Vitamin A stimulates the production and activity of white blood cells, takes part in remodeling bone, helps maintain healthy endothelial cells (those lining the body’s interior surfaces), and regulates cell growth and division such as needed for reproduction.
Vitamin A can’t give you superpowers of night vision or cure your dependence on contact lenses, but eating an adequate amount will support eye health. Beta-carotene, which is a carrot’s main nutrient (responsible for this root vegetable’s characteristic orange color), is a precursor to vitamin A and it helps your eyes adjust in dim conditions.
The two main forms of vitamin A in the human diet are preformed vitamin A (retinol, retinyl esters), and provitamin A carotenoids such as beta-carotene that are converted to retinol.
Preformed vitamin A comes from animal products, fortified foods, and vitamin supplements. Carotenoids are found naturally in plant foods. There are other types of carotenoids found in food that are not converted to vitamin A but have health-promoting properties; these include lycopene, lutein, and zeaxanthin.
The Recommended Dietary Allowance for adults 19 years and older is 900 mcg RAE* for men (equivalent to 3,000 IU*) and 700 mcg RAE for women (equivalent to 2,333 IU).
*RAE- Retinol activity equivalents.
*IU- International units
Many breakfast cereals, juices, dairy products, and other foods are fortified with retinol (preformed vitamin A). Many fruits and vegetables contain beta-carotene, lycopene, lutein, or zeaxanthin.
Leafy green vegetables (kale, spinach, broccoli), orange and yellow vegetables (carrots, sweet potatoes), tomatoes, red bell pepper, mango, beef liver, fish oils, milk, eggs are great sources of Vitamin A.
Vitamin D is both a nutrient we eat and a hormone our bodies make. It is a fat-soluble vitamin that has long been known to help the body absorb and retain calcium and phosphorus; both are critical for building bone. Also, laboratory studies show that vitamin D can reduce cancer cell growth, help control infections and reduce inflammation. Many of the body’s organs and tissues have receptors for vitamin D, which suggest important roles beyond bone health, and scientists are actively investigating other possible functions.
Few foods naturally contain vitamin D, though some foods are fortified with the vitamin. For most people, the best way to get enough vitamin D is taking a supplement because it is hard to eat enough through food. Vitamin D supplements are available in two forms: vitamin D2 (ergocalciferol or pre-vitamin D) and vitamin D3 (cholecalciferol). Both are also naturally occurring forms that are produced in the presence of the sun’s ultraviolet-B (UVB) rays, hence its nickname, the sunshine vitamin.
D2 is produced in plants and fungi and D3 in animals, including humans. Vitamin D production in the skin is the primary natural source of vitamin D, but many people have insufficient levels because they live in places where sunlight is limited or because they have limited sun exposure due to being inside much of the time. The Recommended Dietary Allowance for adults 19 years and older is 600 IU daily for men and women, and for adults >70 years it is 800 IU daily.
Few foods are naturally rich in vitamin D3. The best sources are the flesh of fatty fish and fish liver oils. Smaller amounts are found in egg yolks, cheese, and beef liver. It is also important to get the Vitamin D dose from the early morning sunlight between 8AM to 10AM.
Vitamin E is a fat-soluble vitamin with several forms, but alpha-tocopherol is the only one used by the human body. Its main role is to act as an antioxidant, scavenging loose electrons (free radicals) that can damage cells. It also enhances immune function and prevents clots from forming in heart arteries.
The Recommended Dietary Allowance (RDA) for vitamin E for males and females ages 14 years and older is 15 mg daily (or 22 international units, IU), including women who are pregnant. Lactating women need slightly more at 19 mg (28 IU) daily.
Vitamin E is found in plant-based oils, nuts, seeds, fruits, and vegetables such as wheat germ oil, sunflower and soybean oil, sunflower seeds, almonds, peanuts and peanut butter, spinach, red bell pepper, mango and avocado.
Vitamin K is a fat-soluble vitamin that comes in two forms. The main type is called phylloquinone, found in green leafy vegetables like cabbage, broccoli, kale, and spinach. Some fruits such as kiwi and cucumber also contain vitamin K.
The other type, menaquinones, are found in some animal foods such as meats, eggs and fermented foods like fermented soybeans. Vitamin K helps to make various proteins that are needed for blood clotting and the building of bones. Prothrombin is a vitamin K-dependent protein directly involved with blood clotting.
Vitamin K is found throughout the body including the liver, brain, heart, pancreas, and bone. It is broken down very quickly and excreted in urine or stool. Because of this, it rarely reaches toxic levels in the body even with high intakes, which can occur with other fat-soluble vitamins.
Vitamin C is said to be one of the most important vitamins because of its very many health benefits. Loading up on Vit C is said to be a way to prevent colds and some chronic diseases. Vitamin C, or ascorbic acid, is a water-soluble vitamin. This means that it dissolves in water and is delivered to the body’s tissues but is not well stored, so it must be taken daily through food or supplements.
Vitamin C plays a role in controlling infections and healing wounds, and is a powerful antioxidant that can neutralize harmful free radicals. It is needed to make collagen, a fibrous protein in connective tissue that is weaved throughout various systems in the body: nervous, immune, bone, cartilage, blood, and others.
While mega dosing on this vitamin is not uncommon, how much is an optimum amount needed to keep you healthy?
The Recommended Dietary Allowance for adults 19 years and older is 90 mg daily for men and 75 mg for women. For pregnancy and lactation, the amount increases to 85 mg and 120 mg daily, respectively. However the upper intake limit vitamin C is 2000 mg daily; taking beyond this amount may bring about gastrointestinal distress and diarrhea.
Vitamin C can be found in fruits and vegetables such as Citrus (oranges, kiwi, lemon, grapefruit), bell peppers, strawberries, tomatoes, cruciferous vegetables (broccoli, cabbage, cauliflower) and white potatoes.
These vitamins help a variety of enzymes do their jobs, ranging from releasing energy from carbohydrates and fat to breaking down amino acids and transporting oxygen and energy-containing nutrients around the body.
I am sure we all are familiar with Vitamin B6, B9 and B12, Pyridoxine, Folate or folic acid and cobalamin respectively. But do you know that there are actually eight B vitamins in total.
B5 (pantothenic acid)
B9 (folate [folic acid])
We shall be talking more on the three common B vitamins
Folate, Vit B6 and Vit B12.
Folate is the natural form of vitamin B9, water-soluble and naturally found in many foods. It is also added to foods and sold as a supplement in the form of folic acid; this form is actually better absorbed than that from food sources. Folate helps to form DNA and RNA and is involved in protein metabolism. Folate is also needed to produce healthy red blood cells and is critical during periods of rapid growth, such as during pregnancy and fetal development.
A wide variety of foods naturally contain folate, but the form that is added to foods and supplements, folic acid, is better absorbed. Good sources of folate include dark green leafy vegetables, beans, peanuts, fresh fruits, whole grains, liver, seafood, eggs, fortified foods and supplements.
Vitamin B6, or pyridoxine, is a water-soluble vitamin found naturally in many foods, as well as added to foods and supplements. Pyridoxal 5’ phosphate (PLP) is the active coenzyme form and most common measure of B6 blood levels in the body. PLP is a coenzyme that assists more than 100 enzymes to perform various functions, including the breakdown of proteins, carbohydrates, and fats. It also helps to support immune function and brain health. Vitamin B6 has been widely studied for its role in disease prevention. The vitamin in supplement form shows the most promise for the treatment of pregnancy-induced nausea, but such use should only occur under the supervision of a physician.
Vitamin B6 is found in a variety of animal and plant foods: beef liver, tuna, salmon, fortified cereals, poultry, Some vegetables and fruits, especially dark leafy greens, bananas, pawpaws and oranges.
Vitamin B12, or cobalamin, is naturally found in animal foods. It can also be added to foods or supplements. Vitamin B12 is needed to form red blood cells and DNA. It is also a key player in the function and development of brain and nerve cells. Food Sources of Vitamin B12 include fish, liver, red meat, eggs, poultry, dairy products such as milk, cheese and yoghurt, fortified nutritional yeast or fortified breakfast cereals.
Vitamins and minerals are often called micronutrients because your body needs only tiny amounts of them. Yet failing to get even those small quantities virtually guarantees disease. Just as a lack of key micronutrients can cause substantial harm to your body.
Vitamin deficiencies affect all ages and frequently coexist with mineral (zinc, iron, iodine) deficiencies. The groups most susceptible to vitamin deficiencies are pregnant and lactating women, and young children, because of their relatively high needs for these compounds and susceptibilities to their absence. Some of the most common deficiencies relate to vitamin A, various B vitamins, folate and vitamin D.
Here are a few examples of diseases that can result from vitamin deficiencies:
Scurvy: the hallmark disease of severe vitamin C deficiency, displays symptoms resulting from loss of collagen that weakens connective tissues to skin spots caused by bleeding and bruising from broken blood vessels and also swelling or bleeding of gums, and eventual loss of teeth.
Blindness. In some developing countries, people still become blind from vitamin A deficiency.
Rickets : a deficiency in vitamin D can cause rickets, a condition marked by soft, weak bones that can lead to skeletal deformities such as bowed legs.
There are so many other vitamin deficiencies that can occur and so it is important to load on foods that contain these vitamins to avoid that. When food sources aren’t sufficient, one can now try multivitamins or supplements to boost the supply of vitamins in the body.
It is important to get your vitamins from food sources rather than supplements or pills. However some particular groups may need vitamin supplements such as
- Vitamin D for the sun deprived
- Vitamin B12 for Vegans and the Elderly
- Folic acid for pregnant women.
So it is important to consult a Doctor or Registered Dietitian if you fall in these groups or want to start on any supplements.
We hope you have learnt a few things from the blog today and if you have, kindly share with your friends so they can also learn from it.
We will be continuing on the theme; Nutrient Fact next week on the topic Minerals. We hope you are as excited as we are.
Follow us on all our social media pages;