A snapshot of vitamins and minerals Flashcards
What is beriberi?
Beriberi is caused by a thiamine deficiency (vitamin B1)
Causes of thiamine deficiency includes dietary intake and anti-inhibitors.
Anti-inhibitors - things that prevent absorption of thiamine or breakdown thiamine before it is absorbed
What are vitamins and minerals?
Vitamins are organic substances - made by plants and animals, very fragile compounds
Minerals are inorganic elements - come from soil and water, absorbed by plants/eaten by animals
What are vitamins?
Vitamins have different physiological roles and are individual units (not linked together). Vitamins are essential nutrients as they cannot be made by the body (except vitamin D) hence are required in the diet (only in small quantities). Broad classification of water soluble and fat soluble vitamins
How do you classify vitamins?
Water soluble vitamins are generally excreted in the urine when plasma levels exceed renal threshold. Not stored in large quantities in body tissues - lower risk of toxicity. Absorbed in portal blood
Fat soluble vitamins are stored in greater quantities in body tissues - mainly liver, adipose and cell membranes. Initially enter lymphatic system as part of chylomicron
What are minerals?
Minerals constitute only 4% of total body weight and are responsible for structural functions involving skeleton and soft tissues, regulates functions including neuromuscular transmission, blood clotting, oxygen transport and enzymatic activity. Classified into major and minor trace minerals
What are mineral classifications?
Macronutrients are found in great abundance in the body and are required in large amounts in the diet, more than 100mg/day
Micronutrients are found in lower abundance, termed as trace as concentration in tissues not easily identified, not required in large amounts, less than 100mg/day
What are coenzymes and cofactors?
Coenzymes are small organic carrier molecules that link to enzymes and are essential to the activity of those enzymes. Involved in transferring things from one molecule to another, many coenzymes are derived from vitamins
Cofactors are more general term for small molecules required for the activity of their associated enzyme. Not strictly carrying something - might be stabilising the enzyme or substrate or helping the reaction convert substrates
What is thiamine?
Thiamine serves as a coenzyme in the form of thiamine pyrophosphate (TPP) in a variety of metabolic processes such as energy production
Thiamine is a water soluble vitamin found in a wide variety of foods, including: seeds, beans, pork, spinach and cereal (fortified)
What is thiamine deficiency?
Thiamine deficiency refers to lack of TPP and has adverse consequences on energy production and nutrient metabolism - life threatening. Affects cardiovascular, nervous, muscle tone and immune system
Insufficient intake from the diet includes lower absorption or higher excretion rates than normal due to alcohol dependence’s or HIV/AIDS or use of some medications
Early stages: weight loss and anorexia, confusion, short term memory loss, muscle weakness and CVD symptoms
What is ‘wet beriberi’?
As it progresses to the heart there are rare cases of ‘wet beriberi’ which causes congestive heart failure leading to edema in lower limbs and occasionally death
How can thiamine intake be affected?
Poor intake of thiamine due to a very limited food supply - poor variety - and staple diet of white polished rice
Chronic alcoholism - ethanol reduces GI absorption of thiamine, liver thiamine stores and thiamine phosphorylation
Anti-thiamine factors - react with thiamine to form an oxidised incite product (large amounts of tea and coffee associated with thiamine depletion, mycotoxins and thiaminases break down thiamine)
What is the treatment for beriberi?
Active treatment - thiamine supplementation either orally, IV or intramuscular
