The Role of Biotin in Metabolism and Overall Health

Biotin, also known as vitamin B7 or sometimes referred to as vitamin H, is a water-soluble B-complex vitamin that plays a crucial role in maintaining the body’s overall metabolic health. It functions as a coenzyme, assisting enzymes that transfer carbon and oxygen atoms between molecules within cells. Through these biochemical reactions, biotin helps convert food into usable energy by aiding the metabolism of fats, carbohydrates, and proteins. This makes it essential for supporting the body’s natural energy production and for maintaining normal physiological functions.

One of biotin’s most important roles is in the synthesis of fatty acids and amino acids—key building blocks for healthy cell growth and tissue repair. This contributes to the maintenance of healthy skin, hair, and nails, which is why biotin is often found in beauty supplements. Additionally, biotin supports nervous system function and helps regulate gene expression, further emphasizing its role in sustaining good health.

Biotin can be obtained naturally from a variety of foods. Excellent sources include liver, egg yolks, yeast, nuts (especially almonds and walnuts), seeds, and legumes such as beans and lentils. Certain fish, such as salmon, are also rich in biotin; just two ounces of salmon can provide about 25 percent of the Adequate Intake (AI) for adults. Although there is no established Recommended Dietary Allowance (RDA) for biotin, deficiencies are rare. This is because gut bacteria naturally synthesize sufficient amounts of the vitamin to supplement dietary intake.

In general, a balanced diet provides all the biotin the body needs. However, maintaining diverse food choices—particularly those rich in whole grains, nuts, and eggs—ensures that the body has enough of this vital nutrient to support healthy metabolism, growth, and overall vitality.
The Role of Biotin in Metabolism and Overall Health

Vitamin E-rich foods

Vitamin E is an essential nutrient that serves as a powerful antioxidant, safeguarding cells from oxidative stress caused by free radicals. This protective role is vital in reducing the risk of chronic diseases such as heart disease, cancer, and neurodegenerative disorders. Beyond its antioxidant properties, vitamin E is integral to immune function, helping the body combat infections and maintain resilience. Its benefits extend to skin health, where it aids in reducing inflammation, enhancing moisture retention, and promoting wound healing, making it a staple in skincare products. This nutrient also contributes to overall well-being by supporting healthy vision and balancing hormonal functions.

A balanced diet offers numerous sources of vitamin E, ensuring that this vital nutrient can be easily included in daily meals. Nuts and seeds are among the richest sources. Almonds, sunflower seeds, and hazelnuts are particularly high in vitamin E, with just a small serving meeting a significant percentage of the daily requirement. For example, one ounce of almonds provides about 7.3 milligrams of vitamin E, nearly 50% of the recommended daily intake for adults. Incorporating these as snacks or toppings for dishes is a simple and effective way to boost vitamin E levels.

Vegetable oils are another excellent source of vitamin E. Sunflower oil, safflower oil, and wheat germ oil are particularly rich in this nutrient. A single tablespoon of wheat germ oil contains approximately 20 milligrams of vitamin E, exceeding the daily recommended intake. These oils can be used in cooking, baking, or as salad dressings, offering a versatile means of enhancing dietary intake.

Green leafy vegetables such as spinach, kale, and Swiss chard also provide vitamin E. These vegetables are not only nutrient-dense but also contribute to overall health with their high levels of vitamins A, C, and K. Regular consumption of these greens—whether in salads, smoothies, or sautéed dishes—ensures a steady intake of vitamin E.

Avocados are another valuable source, offering approximately 2 milligrams of vitamin E per fruit. Their creamy texture and versatile flavor make them easy to incorporate into meals such as salads, sandwiches, and smoothies. Additionally, fortified foods like cereals and plant-based milk often contain added vitamin E, making them convenient options for meeting dietary needs.

By embracing a diverse range of vitamin E-rich foods, individuals can harness the full spectrum of benefits this nutrient offers. From protecting cellular health to supporting immunity and skin vitality, vitamin E is a cornerstone of a balanced and healthful diet.
Vitamin E-rich foods

Vitamin A Food Sources

Vitamin A is a crucial nutrient for various bodily functions, and its sources extend beyond just whole eggs, whole milk, and liver. While these foods contain natural forms of vitamin A, it's worth noting that vitamin A is predominantly found in the fat portion of whole milk. Thus, fat-free milk lacks this essential nutrient, but most fat-free milk products in the US are fortified with vitamin A to compensate for this deficiency. Additionally, dried nonfat milk solids are often enriched with vitamin A to ensure adequate intake.

Beyond dairy and liver, numerous fortified foods contribute to vitamin A intake, such as breakfast cereals. These fortified options serve as convenient and accessible sources of the nutrient, aiding individuals in meeting their daily requirements. Importantly, regular consumption of vitamin A-rich foods or those containing beta-carotene, a precursor to vitamin A, is essential for maintaining optimal health. While the body can store vitamin A in the liver, consistent intake is necessary to replenish stores and ensure sufficient levels during periods of low dietary intake. Thus, incorporating a variety of vitamin A sources into one's diet is paramount for overall well-being.
Vitamin A Food Sources

Vitamin B12 Sources and Bioavailability

Vitamin B12, an essential nutrient for human health, plays a vital role in various bodily functions. Its primary functions include supporting red blood cell production, maintaining nervous system health, aiding in energy metabolism, and assisting in the utilization of folate, another important B vitamin. Without sufficient intake of vitamin B12, individuals are at risk of developing vitamin B12 deficiency anemia, which can lead to various health issues.

To meet the recommended daily intake of vitamin B12—2.4 micrograms for adults, 2.6 micrograms for pregnant individuals, and 2.8 micrograms for breastfeeding individuals—it is crucial to incorporate foods rich in this nutrient into our diets. While animal products like shellfish, fish, and dairy are traditional sources of vitamin B12, there are suitable alternatives available for vegetarians and vegans.

Plant-based options such as nutritional yeast and fortified foods are excellent sources of vitamin B12 that can fulfill dietary requirements. Additionally, supplements are readily accessible for those who struggle to obtain adequate levels through food alone.

It's worth noting that the bioavailability of vitamin B12 varies depending on the source and dosage. Absorption rates decline when the body's capacity of intrinsic factor is exceeded, typically occurring at doses between 1 and 2 micrograms. Moreover, the type of food source influences bioavailability, with dairy products offering approximately three times higher bioavailability than meat, fish, and poultry. Similarly, dietary supplements provide a bioavailability roughly 50% higher than that of food sources.

In summary, ensuring an ample intake of vitamin B12 is crucial for overall health and preventing deficiency-related ailments. By diversifying our diets to include both animal and plant-based sources rich in vitamin B12, individuals can effectively meet their nutritional needs and maintain well-being.
Vitamin B12 Sources and Bioavailability

Food sources of vitamin B9

Folate is the natural form of vitamin B9 and it is important in red blood cell formation and for healthy cell growth and function. The nutrient is crucial during early pregnancy to reduce the risk of birth defects of the brain and spine. The vitamin is water-soluble and naturally found in many foods. The synthetic form of folate is folic acid.

Folate plays an important role in protein metabolism and helps to form DNA and RNA. It plays a key role in breaking down homocysteine, an amino acid that can exert harmful effects in the body if it is present in high amounts. It’s also necessary for the production of healthy red blood cells and is critical during periods of rapid growth, such as during pregnancy and fetal development.

Folate is found mainly in dark green leafy vegetables, beans, peas and nuts. Fruits rich in folate include oranges, lemons, bananas, melons and strawberries.

One cup (177 grams) of cooked kidney beans contains 131 mcg of folate, or about 33% of the Daily Value (DV). Meanwhile, one cup (198 grams) of cooked lentils contains 358 mcg of folate, which is 90% of the DV.

In January 1998, the U.S. Food and Drug Administration required food manufacturers to add folic acid to foods commonly eaten, including breads, cereals, pasta, rice, and other grain products, to reduce the risk of neural tube defects.

A diet lacking foods rich in folate or folic acid can lead to a folate deficiency. Folate-deficiency anemia is the lack of folic acid in the blood. Folate deficiency can also occur in people who have conditions, such as celiac disease, that prevent the small intestine from absorbing nutrients from foods. Low levels of folic acid can cause megaloblastic anemia. With this condition, red blood cells are larger than normal.

Men and women ages 19 years and older should aim for 400 mcg DFE. The CDC recommends that all women get at least 400mcg of folate a day, whether or not they plan on becoming pregnant. Pregnant and lactating women require 600 mcg DFE and 500 mcg DFE, respectively.
Food sources of vitamin B9

Vitamin B Complex: Vitamin B5

Vitamin B5, also called pantothenic acid, belongs to the group of water-soluble B vitamins. Pure pantothenic acid is a viscous, yellow oil. It is stable at neutral pH, but is readily destroyed by acid, alkali, and heat.

Calcium pantothenate, a white, odorless, crystalline substance, is the form of pantothenic acid usually found in commercial vitamin supplements due to its greater stability than the pure acid. Pantothenic acid is an essential nutrient that is naturally present in some foods, added to others, and available as a dietary supplement.

It was largely the efforts of research groups associated with R.J. Williams, C.A. Elvehjem, and T.H. Jukes that resulted in the identification of pantothenic acid as an essential dietary factor. Its name originates from the Greek word "pantos", meaning everywhere, as it can be found throughout all living cells.

Vitamin B5 (pantothenic acid): Symptoms of deficiency are fatigue, chronic stress, and depression. Vitamin B5 is needed for hormone formation and the uptake of amino acids and the brain chemical acetylcholine, which combine to prevent certain types of depression.

The chemical structure of pantothenic acid consists of pantoic acid and β -alanine bound in amide linkage.

The main function of this water-soluble B vitamin is in the synthesis of coenzyme A (CoA) and acyl carrier protein. CoA is essential for fatty acid synthesis and degradation, transfer of acetyl and acyl groups, and a multitude of other anabolic and catabolic processes.

CoA is essential to numerous metabolic pathways that sustain life:
• Synthesis of pantothenic acid cofactors (CoA, 4’-phosphopantetheine)
• Cofactor and co-substrate function (CoA, 4’-phosphopantetheinylation)
• Acyl-carrier protein
• 10-formyltetrahydrofolate dehydrogenase
• α-aminoadipate semialdehyde synthase

Pantothenic acid is naturally present in almost all foods. It is also added to some foods, including some breakfast cereals and beverages (such as energy drinks). Foods that are considered to be exceptionally good dietary sources of pantothenic acid include peanut butter (5-8 mg/100 g), liver (5-7 mg/100 g), kidney (4-6 mg/100 g), peanuts (2-3 mg/100 g), almonds (2-3 mg/100 g), wheat bran (2-3 mg/100 g), cheese (1.5 mg/100 g), and lobster (1.5 mg/100 g).

Pantothenic acid in dietary supplements is often in the form of calcium pantothenate or pantethine.

Refining, freezing, canning and cooking food causes losses of pantothenic acid, so a modern processed food diet would be expected to have lower amounts of vitamin B5 than a whole foods diet.

About 85% of dietary pantothenic acid is in the form of CoA or phosphopantetheine. These forms are converted to pantothenic acid by digestive enzymes (nucleosidases, peptidases, and phosphorylases) in the intestinal lumen and intestinal cells. Pantothenic acid is absorbed in the intestine and delivered directly into the bloodstream by active transport.
Vitamin B Complex: Vitamin B5

Riboflavin: Water soluble vitamin

Riboflavin is a water-soluble member of the B-vitamin family. It was first documented in 1879 by Alexander W. Blyth as a yellow pigment found in milk. Riboflavin, chemically, is 7, 8-dimethyl-10-ribityl-isoalloxazine which consists of a flavin isoalloxazine ring bound to a sugar side chain, Ribitol.

Riboflavin is the precursor to the coenzymes, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). FMN and FAD serve as coenzymes for flavoproteins involved in a wide variety of oxidation–reduction reactions in intermediary metabolism.

A shortage of this vitamin may manifest itself as weakness, fatigue, cracks and sores at the corners of the mouth, eye disorders, inflammation of the mouth and tongue, and skin lesions. More advanced deficiency may result in cheilosis, angular stomatitis, dermatitis, corneal vascularisation, anemia and brain dysfunction.

Food sources of riboflavin: legumes, including chick peas, lentils, red and black gram, soya bean, beef, mutton, chicken, duck, fishes, egg yolk.

The estimated average requirement and RDA for riboflavin that cover men and women between the ages of 19 and 70 years old are 0.9–1.1 and 1.1–1.3 mg/d, respectively.
Riboflavin: Water soluble vitamin

Food sources of vitamin B3

Niacin, also known as vitamin B3, the third water-soluble vitamin discovered. Niacin is the generic term for nicotinic acid (pyridine 3-carboxylic acid) and nicotinamide (nicotinic acid amide). Both are used to form the coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) which play essential roles for the development and function of living cells in human body.

Niacin is found naturally in many foods, and is added to some foods.
• Poultry, beef, pork, anchovies and fish
• Some types of peanuts, nuts, legumes, and grains
• Enriched and fortified foods, such as many breads and cereals
• Whole grains and whole meal wheat flour

In general, food rich in protein, with the exception of tryptophan-poor grains (e.g., corn, wheat), can satisfy some of the requirement for niacin. Important food sources of tryptophan are meat, milk and eggs.

The amino acid tryptophan contributes as much as two thirds of the niacin activity required by adults in typical diets.

Peanut butter is an excellent source of niacin. Fruits and vegetables provide useful amounts, depending upon the dietary intake. Other useful sources are whole grain cereals, bread, tea, and coffee.

Human milk contains a higher concentration of niacin than cow’s milk. In plants, especially in mature cereal grains like corn and wheat, niacin may be bound to sugar molecules in the form of glycosides, thus significantly reducing niacin bioavailability.

B3 (niacin) is important as it helps the body to
• convert food into glucose, used to produce energy
• produce macromolecules, including fatty acids and cholesterol
• DNA repair and stress responses.

Most people in the United States get enough niacin from the foods they eat. Niacin deficiency is very rare in the United States.
Food sources of vitamin B3

Fat soluble vitamin: Vitamin E

Vitamins are divided into two groups: water-soluble (B-complex vitamins and C vitamins) and fat-soluble vitamins (A, D, E and K).

Vitamin E, of which there are four different forms (the tocopherol), is fat soluble. The tocopherols have the same name except with the prefix α-, β-, γ-, and ẟ- (the first four letters of the Greek alphabet).

The four compounds are closely related, with some difference in the molecular weight and in the position and number of certain molecular constituents.

Vitamin E is the most powerful natural antioxidant and protecting vitamins A and C, red blood cells, and essential fatty acids from destruction.

Vitamin E is a known biological antioxidant able to quench the lipid peroxidation chain. Vitamin E activity is measured by activity of α-tocopherol equivalents, while β-tocopherol has lower activity.

About 60 percent of vitamin E in the diet comes from vegetable oil (soybean, corn, wheat germ, cottonseed, and safflower). This also includes products made with vegetable oil (margarine and salad dressing).
Fat soluble vitamin: Vitamin E

Vitamins in peanuts

Peanuts botanically named as Arachis hypogaea are consumed in many forms such as boiled peanuts, peanut oil, peanut butter, roasted peanuts, and added peanut meal in snack food, energy bars and candies.

Its role in a heart-healthy diet has warranted tremendous attention among consumer groups and within the scientific community. Peanuts are considered as a vital source of nutrients including several important vitamins.

Peanuts are a vital source for introducing most of the water-soluble vitamins into the human body along with vitamin E which is fat soluble.

*Biotin. Peanuts are one of the richest dietary sources of biotin, which is important during pregnancy. Biotin is a water-soluble vitamin that serves as an essential coenzyme for five carboxylases in mammals. Biotin-dependent carboxylases catalyze the fixation of bicarbonate in organic acids and play crucial roles in the metabolism of fatty acids, amino acids and glucose.

*Niacin. Also known as vitamin B3, niacin an essential coenzyme in metabolic respiratory pathways within the mitochondria. It has been linked to a reduced risk of heart disease.

*Folate. Also known as vitamin B9 or folic acid, folate has many essential functions and is especially important during pregnancy.

*Vitamin E. Vitamin E is known as alpha-tocopherol, and is an anti-oxidative vitamin. It is associated with obstructing the formation of free radicals by preventing the oxidation of unsaturated fatty acids present in consumed foods, respiratory membranes, and mitochondrial matrix in the human body.

*Thiamine. Peanuts are a good source of water-soluble vitamin thiamine (B1), which functions as a coenzyme in carbohydrate and amino acid metabolic pathways It helps your body’s cells convert carbs into energy and is essential for the function of your heart, muscles, and nervous system. This vitamin is known that deficiency of thiamine leads to beri-beri, a disease that can cause problems in the cardiovascular and central nervous system (CNS).
Vitamins in peanuts

Food sources of vitamin D

Vitamin D is a fat-soluble vitamin. This means that human body can store extra amounts of vitamin D. Vitamin D works with calcium and phosphorus for healthy bones, muscles and teeth.

Vitamin D is a nutrient found in some foods that is needed for health and to maintain strong bones. It does so by helping the body absorb calcium (one of bone’s main building blocks) from food and supplements. Human body needs vitamin D to help absorb calcium. Vitamin D may help to prevent or manage some chronic diseases.

The main source of vitamin D comes from sunlight. The high vitamin D deficiency is strongly associated with low sun exposure. The sources of vitamin D in food was limited.

Oily fish such as sardines, pilchards, trout, herring, kippers and eel contain reasonable amounts of vitamin D. Salmon, tuna, and mackerel are among the best sources. Beef liver, cheese, and egg yolks provide small amounts. Mushrooms provide some vitamin D. In some mushrooms that are newly available in stores, the vitamin D content is being boosted by exposing these mushrooms to ultraviolet light.

Now there are many kinds of foods which contain fortified vitamin D, particularly milk products, biscuits, and cereals. Margarine, some breakfast cereals, infant formula milk and some yoghurts have added or are ‘fortified’ with vitamin D.

People can get vitamin D from some foods including fortified foods and everyone is recommended to take a supplement, especially during autumn and winter.

Vitamin D is found in supplements (and fortified foods) in two different forms: D2 (ergocalciferol) and D3 (cholecalciferol). Both increase vitamin D in the blood.
Food sources of vitamin D

The best foods with Vitamin C

Vitamin C or ascorbic acid has been described as the major waters-soluble antioxidant in human serum and has several other essential functions in the body. The recommended Dietary Allowance for adults is 60 mg/day. Humans cannot produce vitamin C in their own bodies and must obtain it from food sources.

In the United States, the foods that are the highest contributors of vitamin C are orange juice, grapefruit, tomatoes and tomato juices and potatoes.

Other good sources of vitamin C are vegetables such as broccoli, cabbage and other green leafy vegetables, pepper, mangoes, papaya and strawberry. Some types of meat products, such as brains, liver and kidneys were found to retain vitamin C.

For practical reason, citrus and other fruits are good daily sources of vitamin C, as they are generally eaten raw and are therefore not subjected to cooking procedures that can destroy vitamin C.

In addition to naturally occurring sources of vitamin C, fortified foods and vitamin supplements provide important sources of this vitamin for Americans.
The best foods with Vitamin C

Fruit sources of vitamin

Fresh fruits and vegetables contribute about 91% of vitamin C, 48% of vitamin A, 27% of vitamin B6, 17% if thiamin and 15% of niacin to the U.S diet.

Medical research suggests that the antioxidant A, C and E protect against certain diseases.

Vitamin A: apricot, peach, cherry, orange, mango, papaya, persimmon, pineapple, cantaloupe, watermelon

Vitamin C: strawberry, orange, grapefruit, kiwifruit, pineapple, banana apple, cantaloupe

Niacin: peach, banana, orange, apricot

Riboflavin: banana, peach, orange, apple, avocado

Thiamin: orange, banana, grapefruit, apple

Vitamins are nutrients required for specific functions in the body. Of the vitamins are not consumed in sufficient quantities, deficiencies diseases develop. The prevention of vitamin deficiency diseases, among others led to the establishment of dietary guidelines by various national governments by the FAO/WHO.

The guiltiness recommended eating five or more servings of fruits and vegetables a day, including two or four servings of fruit (a fruit serving is equal to one piece of apple or a half cup of sliced fruit for example).
Fruit sources of vitamin

Phylloquinone

The major dietary source of vitamin K, the form found in green plants, is generally called vitamin K1 but it is preferably called phylloquinone. It was discovered in higher plants nearly 75 years ago by Henrik Dam but was recognized only a little over a decade ago as an electron carrier between the primary acceptor and inter-polypeptide iron-sulfur center FeS-X in photosystem.

Green leafy vegetables especially spinach (380 ug/100 g), cabbage (145 ug/100 g), broccoli (180 ug/100 g) and Brussels sprouts (177 ug/100 g) supply substantial amounts of phylloquinone.

Certain vegetables oils (soybean, cotton seed, canola and olive) also are good sources. The phylloquinone content of oils varies considerably, with soybean oil (190 ug/100 g) and canola oil (130 ug/100 g) quite high and corn oil (3 ug/100 g) a very poor source.

Exposure to light degrades vitamin K, so the phylloquinone content of oils varies not only with brand and batch but also with storage time if the oil are bottled in transparent container. Therefore, vegetable oils may not be a reliable source of vitamin K.

Phylloquinone was reported in green, brown and read algae and also in the blue-green alga Nostoc. In the brown, red and blue-green algae there was more phylloquinone present compared with plastoquinone than there was in the higher plants. In fruit and in petals phylloquinone was present in detectable quantities.
Phylloquinone