Vitamins and Minerals: MD140

• MD140 will cover Vitamins and Minerals.
• Session 1 is on Wednesday, January 22nd, 9 am.
• Session 2 is on Tuesday, January 28th, 11 am.
• Lecture slides and pre-recorded lectures are available on Canvas.
• 'Test your knowledge' exercises are available.
• Recommended textbooks are Lippincott’s Illustrated Reviews - Biochemistry and Medical Biochemistry, 5th edition by Baynes & Dominiczak.

Content Outline

• General introduction to vitamins and minerals
• Vitamins, including general information, fat-soluble vitamins (A, D, E, & K), and water-soluble vitamins (B family & C)
• Minerals, including general, major, trace, and ultra-trace minerals

Micronutrients

• Vitamins and minerals are essential for metabolism.
• They form prosthetic groups or co-factors of enzymes.
• They can act as hormones like Vitamins A & D.
• Micronutrients are crucial for cell growth, proliferation, differentiation, and immune mechanisms.

Learning Objectives

• Explain the biological function and necessity of micronutrients.
• Clarify the connection between a micronutrient's biochemical function.
• Clarify the pathophysiological consequences of its deficiency.
• Discuss the consequences of micronutrient deficiencies.

Deficiency and Toxicity

• Deficiency can result from inadequate intake, inefficient utilization, increased loss, poor absorption, or increased demand.
• Multiple deficiencies are more common than single deficiencies.
• Toxicity can result from the excess.

High-Risk Patients for Deficiencies

• Individuals with liver and renal diseases
• Undernourished individuals
• Those with malabsorption issues such as in Irritable Bowel Syndrome and Short Bowel Syndrome
• Those with substance abuse issues
• Geriatric patients
• Individuals with chronic inflammatory disease

Dietary Reference Intakes (DRI)

• DRI values are the amounts of nutrients required to prevent deficiency and maintain optimal health.
• DRI is established based on evidence from research studies.
• DRI varies for nutrients based on life stage, physiological state, and gender.

Standards of Requirement

• Estimated Average Requirement (EAR): Meets the requirement of 50% of a healthy population.
• Recommended Daily Allowance (RDA): Meets the requirement of 98% of the population.
• Adequate Intake (AI): Estimate based on a group of healthy people when no RDA is known.
• Tolerable Upper Limit (UL): Highest daily dose that poses no risk.

Vitamin Overview

• Vitamins are chemically unrelated compounds that are not synthesized by humans but are essential for the body.
• Vitamins are discoverable in milk and butter.
• Most vitamins are found in grains, vegetables, fruits, milk, and meat & beans.
• Maximal vitamin absorption occurs in the small intestine.
• Fat-soluble vitamins include A, D, E, and K.
• Water-soluble vitamins include the B vitamins (B1, B2, B3, B5, B6, B7, B9, B12) and Vitamin C.
• Vitamins promote and regulate body activities.
• Each vitamin has a unique role, and B vitamins are coenzymes.

Fat-Soluble Vitamins

• Stored in tissue and associated with body fat
• Fat-soluble vitamin circulating concentrations are constant and low; measurements within the cell are the most accurate for diagnosis.
• Absorbed with fat
• Deficiencies originate from fat malabsorption, liver or gallbladder diseases, inflammatory bowel disease, and cystic fibrosis.

Water-Soluble Vitamins

• These vitamins can not be stored in the body.
• Must be regularly supplied in the diet
• Excess is secreted in urine

Vitamin A

• Vitamin A refers to retinoids (retinol, retinal, retinoic acid).
• Provitamin A refers to carotenoids.
• The collective term describes related biologically active molecules: retinol and retinal.
• Retinoic acid is its active form.
• 1mg of retinol is equivalent to 12mg beta-carotene.

Retinol

• Functions as a prosthetic group of opsin to form rhodopsin.
• One photon can switch retinal to trans, it conformation change.
• A nerve impulse is created and retinal is released.
• A deficiency causes night blindness, while severe deficiencies cause blindness.
• Blindness is most common in the developing world and with liver disease/CF.
• Golden Rice will produces beta-carotene, this has now been approved for safe distribution in the Philippines since 2021

Other functions and toxicity of Vitamin A

• Key functions of retinoic acid due to acting as transcription regulator.
• Binds nuclear receptor (RAR)
• Genes regulating growth, embryonic development and tissue differentiation.
• Decreases Keratin levels within the skin
• Acts as an antioxidant
• Treatment of psoriasis, severe acne and promote growth, used and available in many dermatological or medical treatments
• Excess is toxic and teratogenic.
• Toxic excess is impossible to develop by ingesting normal food, due to overconsumption of food supplements and medical treatments
• Results of ingesting supplement or medical treatment

Vitamin D

• Normal dietary forms are ergocalciferol (VitD2 in plants) and cholecalciferol (VitD3); calcitriol is the active metabolite made in the kidney.
• Good source : Fatty fish, liver, egg yolk. Not milk unless fortified
• Cholecalciferol (Vit D3) is made in the skin from cholesterol via UVB rays.

Vitamin D Synthesis and Role in the Body

• Active Vitamin D is formed by successive hydroxylation of D3 in the liver (calcidol) and kidney (calcitriol).
• Regulation of calcium absorption and bone health
• Maintenance of normal bone structure.
• Vitamin D functions as a steroid hormone, and binds to a nuclear receptor protein that increases expression of calcium binding protein genes.
• Achieves maintenance of calcium plasma concentration by reducing excretion and mobilizing bone minerals.
• Normal Function required normal function of parathyroid gland and the immune system

Vitamin D Deficiency

• The main role to regulate calcium absorption.
• A deficiency results in soft bones, rickets (insufficient mineralization of teeth), and osteomalacia (demineralization of bones).
• Calcium absorption is regulated by calcium intake.
• Those underexposed to sunlight are most at risk, 30 min of face exposure a day helps.
• Supplement is required if increased consumption of calcium occurs or during cooler months.
• Consuming to much can lead to calcification of soft tissue.
• Very hard to get through sun exposure alone

Vitamin E

• Dietary vitamin E is a mixture of compounds called Tocopherols, only alpha-tocopherol is active for human
• Functions primarily as a fat-soluble antioxidant
• Pure vegetable oils; egg yolk; wheat, wholemeal bread and cereals; nuts and sunflower seeds.
• RDA: 15 mg/day
• Multiple Roles in Immune regulation, cellular signaling / expression and regulation
• Reduces action or affects cells by binding and reducing PKC and arachidonic acid
• Necessary in the the reproductive cycle.

Vitamin E is an Antioxidant

• Absorbed by the small intestine.
• Lipoproteins provide vitamin E to the body, delivered in chlyomicomns.
• Protects unsaturated fatty acids and cell membranes.
• A deficiency causes lipid misabsorption.
• Newborns are most at risk of oxidative radicals.
• Vitamin E structure is lipid based with a carbon chain, and protects the membrane

Vitamin K

• Refers to a group of carbon based compounds that vary in the 3-carbon chain
• K1 Circulating of the bodies system, blood clotting
• K2 Stored in the hapatic stores, such as the liver
• K3 Is the ismenadione Synthetic form (artificial)
• Functions to perform co-enzymes during blood clotting
• absorption depends on abilities of the bodies to absorb fat

Functions of Vitamin K

• Green leafy veg, fruits and dairy products, vegetable oils and cereals are great sources of Diet
• synthesized by intestinal microflora
• AI - 90 / 120mg per day
• Dietary Deficiency not seen except new borns
• Deficiencies most common for those with liver disease

Vitamin K in the Body

• vitamin K production needed to perform co-enzymes to modify coagulation
• Carboxylation of a residue
• For production of thrombin + is also the health of blood vessels
• Common uses in Warfarin, blood thinning during thrombotic, also inhibit vitamin action

Water-Soluble Vitamins

• B vitamins are involved in hematopoiesis (folic acid and B12) and energy release (thiamine, riboflavin, niacin, biotin, pantothenic acid).
• Pyridoxine, Pyridoxal, and Pyridoxamine.

Vitamin B9 - Folic Acid

• Folate, Family of Compounds,
• Synthesis and production of of choline, Senne, Glycine
• Tranfer reactions (methylation)
• Synthesis of and and pyrimidines
• Deficiency can cause anencephaly and premature birth

Vitamin B9 – Folate: Common Deficiency

• Pregnancy and Lactation, dividing cells, requirements in blood volume.
• Issues with Neural Tube defects
• Deficiencies from alcholism, dialysis and liver diease, poor absorption

Vitamin B9 Folate deficiency: Adult Megaloblastic Anemia

• Defects in Nucliec synthesis due to large cells in bone marrow, and losses in appitate
• Cannot be distinguished from Vitamin B12 deficiency

Reminder

• To watch videos 2.3.1 and 2.3.2 for next week.
• Next week will focus on remaining "Soluble Vitamins" and then discussion of "Minerals" next week

This lesson provides an overview of vitamins and minerals, essential micronutrients for metabolism and various biological functions. It covers fat-soluble and water-soluble vitamins, major, trace, and ultra-trace minerals. Learn about their roles as co-factors, hormones, and their importance in cell growth and immunity.