vitamins

fat-soluble (lipophilic) vitamins: A, D, E, K

water-soluble vitamins: C, B vitamins

• b vitamins are not themselves sources of energy but are required for cells to get energy from macronutrients

provitamin A and beta carotene: carrots, sweet potatoes, pumpkin, cantaloupe, apricots, green leafy vegetables (spinach, kale)

• dietary retinoids: animal products (meats, liver, eggs, fortified milk, dairy products)

• absorption of cooked food is more efficient because the heat helps to release carotenoids from the plant foods

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vitamin A = retinoids

=> retionol is typically the form that is most often called vitamin A

• other forms: retinal, retinoic acid => can be converted => retinol to retinal and back and retinal to retinoic acid

• can also be derived from some carotenoids: beta-carotene. => can be converted in the human gut to retinoids but typically the conversion is not very efficient

RAE

=> Retinoal activity equivalents: 1 microgram retinol = 12 micrograms of beta-carotene

light absorption and the process of vision in the eye

• retinoic acid helps control the expressions of many genes => effects related to health and diseases

  
  

• from chronic low intake, problem in developing countries

• - secondary deficiency of Vitamin A can occur even with normal dietary intake if there is a problem with the storage or mobilization of the vitamin => liver diseases

• can lead to xerophthalmia (dry eye) which may increase risk of infections and lead to blindness => mainly in developing countries

• other problems: lower immune function, abnormal structure and function of epithelial tissues (skin and mucous membranes that line the gastrointestinal tract), reproduction and embryonic development

developmental malformations of the fetus during pregnancy with high intake of retinoid form Vitamin A (not carotenoids)

• intakes above UL can be toxic to liver, skin, bone, other organs

• we can make it out of sunlight

• sources: salmon, tuna, sardines (D3)

• mushrooms (D2) if they are exposed to UV light during growth

• D-fortified foods: margarine, butter, milk, yogurt, dairy products

• body hormone: regulates expressions of many genes in the cell => maintaining the health of the nervous system, immune system, and skeletal system

• bone health => can increase calcium absorption in the gut

• results in bone diseases => rickets in children; osteomalacia in adults

• low intake and low sun exposure

• sunscreens can prevent vitamin D production in the skin

• People with darker skin can produce less vitamin D through similar exposure to sunlight compared to a light-skinned person

• deficiency can result from very-low-fat diets or through liver disease that effects activation of vitamin D3

• plant foods: green leafy vegetables such as spinach, kale and other members of the cabbage family

• - mostly K1 phylloquinone form

• typically only 10-20% of K1 present in these foods is absorbed by the body

• animal products such as meats, cheeses and other dairy, eggs, seafood, contain K2 or menaquinone form

• K2 produced by bacteria in large intestine

• most likely to occur from supplements

• can be toxic: extremely high levels can result in calcification and damage to many tissues and organs in the body: including kidneys

• participation in the complex process of blood clotting

• deficiency increases risk of hemorrhage (abnormal bleeding)

  • deficiency is rare: newborns are at greatest risk because of low transfer of vitamin K to the fetus during gestation and the low levels in breast milk and large intestine is not yet colonized by bacteria

plant oils, nuts, whole grain foods, avocados, spinach, cauliflower

• same amounts in animal products: fish, butter, eggs

• alpha tocopherol is the form with highest vitamin E activity

• antioxidant in lipid environments: lipoproteins and cell membranes

  • can neutralize free radicals and prevent some damage

    • gets neutralized by vitamin C => regenerates tocopherol

• effects on gene expression and enzyme activity

• increases oxidative damage

• supplementation can lower risk of cancer, alzheimer and dementias, coronary hear disease, eye disease => not proven yet

• proven: benefit of supplementation in cases of non-alcoholic fatty liver diseases (NAFLD)

rare => 20 x RDA

• serious injury to the lungs

• high levels a vitamin E acetate added to the vaping liquids may be involved in this lung injury

• red sweet peppers, kale, cabbage family, blackcurrants, oranges, citrus fruits

• antioxidant and coenzyme in the body processes such as collagen formation, production of dopamine and carnitine

• not proven: benefits against cardiovascular diseases, cancer, dementia, ciruses

• excess can be excreted in the urine

• possible problems with intake lower than 500 mg (even though the UL is 2g)

• high intake can contribute to iron overload in the body

• body always produces free radicals as part of energy metabolism => but: environmental exposure to smoke, radiation, heavy metals, and other contaminants can increase reactive oxygen species (ROS)

• ROS and other high reactive species can cause oxidative damage in the cells and tissues of the body

  • can increase risk of chronic diseases, contributed to gain

  
  

• antioxidants: vitamin C and E, flavonoids, phytochemicals

• endogenous antioxidants made by the body: glutathione, various proteins including blood-iron carrier transferrin and intracellular selenium-enzymes (glutathione peroxidase)

• damage cant be fully prevented => another line of defense that can help lower the risk: repair of damage (repair of DNA)

• whole grain products, enriched cereals, pork, meta, vegetables and fruits

• thiamine pyrophosphate (TPP): a coenzyme for many metabolic reactions in the body

• necessary for cells to obtain energy from dietary carbohydrates

• chronic deficiency results in beriberi: fatal disease => muscle weakness and degeneration of the nerves

• FAD: Flavin adenine dinucleotide

• FMN: flavin mononucleotide

• participate both in many metabolic reactions as coenzymes => energy production

• plant foods: green leafy vegetables, legumes and nuts, animal products, dairy

• peanuts, mushrooms, wheat bran, sunflower seeds, salmon, fish, poultry, meats

• fortified foods: breads + cereals

• compromises cellular energy production => neurological and dermatological symptoms

NAD+ AND NADP+ => Nicotinamide adenine dinucleotide and phosphorylated form)

functions

• coenzymes in metabolic reactions => for energy production of cells

• chronic deficiency results in skin lesions and neurological symptoms; dysfunction and dementia => characteristic of pellagra!

• niacin can be made by body through tryptophan but not enough!

  • if diet is highly dependent on corn => risk of deficiency increases => low tryptophan content and low digestibility

  • through alkali treatment of ground corn => increasing niacin bioavailability => making corn tortillas

supplementation of niacin:

• potential benefits: plasma lipids => lowers triglycerides and LDL cholesterol but harmful side effects: liver toxicity, glucose intolerance

supplementation of nicotinamide

• fewer reported harmful side effects but also not beneficial effects on plasma lipids

• used to treat pellagra and acne

• meats, dairy and other animal products

• banana, watermelon, fruits and vegetables

• dark chocolate, nuts, yeast

• fortified foods: cereals

• pyridoxal phosphate (PLP)

• coenzyme for synthesis of amino acids, hemoglobin, neurotransmitters (dopamine, adrenaline), production of vitamin niacin from tryptophan

• gluconeogenesis

• metabolic reactions: production of selenoproteins in the cells

• dermatitis, neurological dysfunction (nerve damage), microcytic hypochromic anemia, immunodeficiency

• high dose use over long term can also cause nerve damage

• in many different foods

• very small amounts needed for health

• eggs, yolks, peanuts, liver, cheese, yeast foods, avocado

• produced by bacteria in human large intestine => not known about the availability of it

• active: biotin + lysine => biocytin

• participates in production of fatty acids, gluconeogenesis, breakdown of carbohydrates and fat for energy

• metabolism of branched-chain amino acids

• rare

• in a few rare genetic diseases

• with use of medications (some anti-epileptic drugs)

• symptoms: neurological and dermatological problems

• many food sources in plant and animal origin

• needed for the production of coenzyme A (CoA), for metabolic reactions => obtain energy from macronutrients

• peanuts, nuts, green leafy vegetables, orange juice, sunflower seeds, legumes, fish, cheese, poultry, animal livers

• women planning pregnancy: deficiency increases risk of birth defects => spina bifida (incomplete closure of neural tube) during development

  • RDA 50% higher for women in the early stages of pregnancy

  • not recommended to eat a lot of liver: has high levels of vitamin A retinoid => accumulates toxins to which the animal may have been exposed

• folate supplements may prevent detection of pernicious anemia => potentially problem due to long term vitamin B12 deficiency

Tetrahydrofolic acid (THFA)

• coenzyme => synthesis of genetic material and for cell division

  • chronic deficiency can lead to defects in DNA, cell division

  • lead to megaloblastic anemia => large immature red blood cells form in the bone marrow

• animal origin

• B12 only produced by bacteria-like organisms: colonize the gut of animals and produce the B12 that is found in meats and other animal products

  • human body can also produce it but almost everything is excreted from the body

• methylcobalamin and adenosylcobalamin

• methylcobalamin: important for production of biactive folate (THFA) and therefore participates in DNA synthesis and cell division => deficiency can lead to megaloblastic anemia

1. RF produced by salivary glands, protects B12 from stomach acid

2. Intrinsic Factor IF produced by stomach parietal cells, stomach acid also helps release B12 from foods and low acid production

3. Pancreatic proteases in duodenum release B12 from R factor, then IF binds B12 to protect it and promote its absorption

4. IF-B12 is absorbed by enterocytes and in the portal circulation the B12 is transferred to a different carrier protein => transcobalamin delivers it to cells throughout the body

• loss of nerve cell integrity and function => due to insufficient intake or due to a condition (pernicious anemia) that results from loss of intrinsic factor (IF) production

  • IF is important for absorption of B12 by cells of small intestine

• Vegans: should supplement B12 or consume B12-fortified foods or include yeast in their diet

• Elderly people: absorption is more efficient from supplements than from foods => and they have more problems with stomach acid production as well as production of IF

• more fruits and vegetables

• ensuring sufficiency of vitamins B12, folate, A, D, C, E and minerals, phytochemicals and dietary fiber

cancer - cells that have escaped normal growth and death controls

• abnormal cells have high rates of cell division and often invade other tissues in the process of metastasis

• carcinogenesis is influenced by genetics and environmental factors, including diet

• cancer through diet: deficiencies of protective nutrients and phytochemicals, and by excesses of harmful substances (carcinogens)

• high caloric intake, excessive body fat

• diets high in fat (animal products) and consumption of red metas

• chronic high alcohol consumption (oral, esophageal and stomach cancer)

• high temperature cooking methods (frying, flame grilling) produce substances such as polyaromatic hydrocarbons and heterocyclic amines that are potential carcinogens

  • PAHS (polyacromatic hydrocarbons) can act at the initiation phase; others promote phase of cancer cell growth

• D3 is build in our skin from 7-dehydrocholesterol upon exposure to sun/ UV light

• D3 is then activated through hydroxylation reactions in liver and kidney

• scurvy

• abnormal connective tissue (due to its role during the collagen process)

• high amounts of free iron, copper and some other minerals can cause oxidative damage

1. initiation

2. promotion : mutation established & passed on...growth promotion of mutant cells

3. progression: e.g., metastasis or spreading of cancer cells throughout the body