Everyone is well aware that a well balanced diet can provide them with they should be taking multivitamin/mineral supplement, but not many fully understand why. The minerals in your food are obtained from minerals in the soil, but if the soil is depleted there will be little to no minerals in the soil. Vitamins are formed naturally in plants, but no one food has all the vitamins you require on a daily basis. Everyone should take a supplement to fill in the gaps, and to promote health and vitality. However, not all supplements are created equal, and many forms of minerals and vitamins may not be absorbed. We will begin with the vitamins and their essential roles in human health.
Vitamins are classified into one of two groups, fat-soluble or water- soluble, and the group a vitamin belongs to is determined by how the vitamin is absorbed. How each vitamin is absorbed is complex, but can be simplified. If absorbed directly through the intestinal lumen into the blood stream, the vitamin is classified as water-soluble. If absorbed along with dietary fat, and transported to the liver before entering the bloodstream, the vitamin is considered fat-soluble. Fat-soluble vitamins can only enter the bloodstream via the lymphatic system. Vitamins are responsible for hormone production and regulation, cellular functions, and overall homoeostasis of the body. Each vitamin has a specific function in the body and if the vitamin is absent, an individual can become ill, and possibly even die.
Water soluble vitamins are more numerous than their fat-soluble counterparts and include vitamin C and the many different types of vitamin B. Many water-soluble vitamins are heat-sensitive, and can be destroyed by cooking or processing, thus eating fortified or raw foods is important to getting enough of these vitamins.
Vitamin C, or ascorbic acid, is the most well known vitamin and obtained from many fruits and vegetables, such as berries, citrus fruit, and brassica vegetables. Ascorbic acid is easily absorbed into the bloodstream and utilized by the body, thus is a highly bio-available vitamin. Vitamin C is important in collagen production and rejuvenation, keeping skin and tissues healthy, metabolism of proteins and fats, and is a potent anti-oxidant. An adult should get at least 60mg a day to prevent deficiency, which can lead to a disease known as scurvy.
Vitamin B has many different forms, each with a specific yet vital function in the human body. Vitamins B1, B2, and B3, also known as thiamin, riboflavin and niacin respectively, each play a specific but functionally different role in glucose metabolism and cellular energy production. Thiamin is found in low concentrations in many foods, and fortified in milk, milk alternatives and cereal grain products. Beri beri is the disease caused by thiamin deficiency, and can cause edema, and/or mental and cardiovascular problems. The average adult should consume 1.3mg of thiamin daily to prevent deficiency. Riboflavin has an additional function as B6 cannot be converted into a useable form without the presence of riboflavin. Riboflavin is present in milk and milk alternatives, liver and meat, and fortified grain flour. 1.6mg of riboflavin is required daily to prevent deficiency symptoms. Riboflavin deficiency is not fatal but can cause skin problems, such as lesions and dermatitis. Niacin is available as nicotinic acid or nicotinamide, the common supplemented form being nicotinic acid. Aside from niacin’s metabolic role, niacin can have a positive impact on overall cardiovascular health and has been shown to lower blood pressure. Tryptophan, an amino acid, is converted to niacin, thus the daily intake is expressed as niacin equivalents, or NE, and 1NE of niacin is roughly equivalent to 60mg of tryptophan. Tryptophan can be found in all protein sources. Taking a high dose of niacin can cause an event known as a niacin flush, a reddening of the skin caused by blood vessel dilation just below the skin. Niacin deficiency causes a condition called pellagra, the symptoms progressing from dermatitis, diarrhea, dementia and eventually death.
Vitamin B6 is a multifunctional vitamin, being utilized in many roles in the human body. The primary role of B6 is the breakdown of proteins into amino acids, which can impact niacin status as previously discussed. Vitamin B6 is essential to the human nervous system, as B6 is involved in the synthesis of neurotransmitters, chemical signal hormones, such as serotonin, dopamine and epinephrine. Vitamin B6 is also involved in the production and regulation of steroid hormones. The process to convert glycogen to glucose occurs during fasting and strenuous exercise. Another important function of B6 is red blood cell formation, particularly the formation of heme, the oxygen carrying component of haemoglobin. Finally, B6 also plays a small role in immune function regulation, a process which is still under investigation. Vitamin B6 is found in many meats, grains, nuts, vegetables, and bananas, and the average adult requires 1.8mg a day to prevent becoming deficient. As vitamin B6 has many functions, being deficient has many symptoms, such as sleeplessness, dermatitis, irritability, and depression.
Folate, also called folacin and folic acid, is another vitamin with many functions throughout the body. Folate is critical to DNA and RNA synthesis and repair, required processes in every cell that actively divides, such as skin, blood cells, intestinal lumen, and sex cells, such as sperm. Folate is especially important to children and women attempting to get pregnant or are pregnant, as there are many repidly dividing cells in need of DNA and RNA. Deficiency during pregnancy leads to neural tube defect and can cause loss of life. Folic acid is the best absorbed and adults should get at least 220 mcg a day, more if trying to conceive. Symptoms of deficiency in adults include anaemia, weakness and depression. A cobalamin deficiency may be masked by a folate deficiency because the same type of anaemia is cause and separate testing must be used to determine the cause. Folate can be found in fruits, veggies, seeds, and legumes
The largest and most structurally complex B-vitamin is B12, or cobalamin. Cobalamin is the only vitamins to require a receptor, or ‘helper’, to be absorbed into the body. Due to the need for a receptor to be absorbed, cobalamin absorption can be inhibited by gastric disorders, such as pernicious anaemia, colitis or atrophic gastritis. Cobalamin plays a role in metabolism, and neurological function, but the largest role fulfilled by cobalamin is the formation of red blood cells. The average adult requires 2mcg a day to avoid deficiency, and sources include meats, including fish and eggs, and some forms of algae. Cobalamin deficiency is characterized by memory loss, tiredness, weakness and dementia and can take up to 7 years to occur. A cobalamin deficiency can also be masked by a folate deficiency.
Biotin is a B-vitamin important to cellular growth and renewal, and cellular processes. Many enzymes are biotin-dependent and without biotin, cellular growth and renewal, and cellular functions would not occur. Biotin is found in many food sources, but is bound to a protein that inhibits its absorption. Pancreatic enzymes can remove the protein and allow biotin to be absorbed. Symptoms of biotin deficiency include hair loss, dermatitis, depression, lethargy and even hallucinations. To avoid deficiency, the average adult requirement for biotin is 30mcg a day.
Our final water-soluble vitamin is pantothenic Acid, also called vitamin B5. Pantothenic acid is very important in metabolism of carbohydrates and fatty acids, and is also very important to cellular energy production and the synthesis of cholesterol in the body. Pantothenic acid has been shown to aid in accelerated wound healing and even lowing cholesterol. Similar to biotin, pantothenic acid must be freed from a protein before it can be absorbed and used in the body. Pantothenic acid is widespread and found in meats, dairy, whole grains, and legumes, allowing the average adult to easily acquire 7mg a day. Deficiency is rare but presents as burning sensation in the extremities, known as Burning Feet Syndrome.
There are four vitamins considered fat-soluble; vitamins A, D, E, and K. Vitamin A has several different forms and the compounds are known as retinoids. Retinyl ester is the form that is found in food and also stored in the liver. Foods rich in retinyl ester include fish, meat, dairy, and egg yolks. In plant food sources, compounds known as carotenoids supply retinyl ester. Carotenoids can be found in orange and yellow fruits and vegetables, dark green vegetables and tomatoes. Once absorbed into the body, vitamin A is used for several functions. Retinal is the form of vitamin A responsible for vision and the ability to adjust to changes in brightness. Retinoic Acid is the form of vitamin A responsible for reproduction, growth, immune system function and cellular health. Vitamin A deficiency can lead to a condition called Night Blindness, where vision recovers slowly after a bright flash of light. Night blindness is an early indicator of developing deficiency and continuing deficiency can lead to complete loss of vision. Deficiency also causes retarded growth, failure to reproduce and decreased immunity. As vitamin A is stored long-term in the body, toxicity can be caused by consuming too much of this vitamin. Excess can cause headache, vomiting, liver damage, hemorrhage, and even coma. Vitamin A is also a teratogenic, causing birth defect if too high in pregnant mothers. The recommended daily intake for vitamin A is 600mcg a day for adults, 700 for pregnant mothers.
Vitamin D is synthesized in the presence of sunlight but is also available in fish and fortified milk and milk alternatives. As a multifunctional vitamin, an individual should make sure to consume the recommended 5mcg a day to maintain good health. Vitamin D has not toxicity linked to higher dosages and many now take up to five times the recommended intake daily. Vitamin D is critical to calcium and phosphorus homoeostasis in the body by assisting the kidneys in recovering calcium and phosphorus if needed. Vitamin D aids in bone growth and maintenance, and ensured healthy bone density. Vitamin D is also shown to help regulate immune function and aid in disease prevention. Vitamin D deficiency can lead to improper bone formation in children, a condition known as Rickets, or loss of bone density in adulthood, a condition called osteoporosis. Both conditions are link to low dietary calcium and lack of physical activity.
Vitamin E, also known as tocopherol, contributes in many roles in the body, the best known function being its potent anti-oxidant ability. This vitamin protects cells and molecules from oxidant damage that may cause harm to the body or inhibit the functions of cells. Vitamin E also contributes to gene expression and immune function, but most commonly scavenges for anything that may cause oxidative damage. Vitamin E can be found in seed oils, and some fruits, such as avocado and pumpkin and the average adult should consume 10mg a day.
Vitamin K is available in three forms for absorption; phylloquinone, menaquinone and menadione. Phylloquinone is the form found in plants, menadione is the synthetic form found in supplements, and menaquinone is the form made by intestinal bacteria, which is also the form used in the body. The first function of vitamin K is blood clotting. Vitamin K, along with calcium, is responsible for initiating the cascade to form a blood clot. Without vitamin K, an individual would not be able to stop blood flow if injured or if a blood vessel ruptures. Secondly, vitamin K is used to synthesize bone proteins and thus supports the growth and maintenance of bones. There are no toxic effects associated with vitamin K, but deficiency can cause hemorrhages. Infants are the most susceptible to deficiency as breast milk is low in vitamin K and intestinal bacteria are not yet established to make menaquinone. The daily intake recommended for adults id 80mcg.
Many vitamins are essential to several functions in the human body. Minerals too have many functions and many vitamins rely on minerals to carry out cellular functions. Part two will explore the use of minerals in the human body and identify the best sources of food.