Lecture 24 Flashcards
What are the characteristics of vitamins? What about minerals?
vitamins are essential, individual, organic molecules which do not provide energy when broken down, if absent or low in the diet deficiency symptoms appear. They are oonly required in small amounts, with bioavailability refering to the amount of it which is absorbed and used. They are fat soluble (vitamins A, D, E, and K) or water soluble (vitamin C and B vitamins (B1-B12)).
Minerals are essentially the same as vitamins but are non organic rather than organic. Minerals are refered to as trace elements if there are less than 5 grams in the body.
How can we tell if people are getting enough vitamins and minerals?
We can tell if we get enough vitamins and minerals from the food we eat, by examining people, e.g skin colour, eyes, hair. Also via anthropometry (energy balance/growth, particularly good for children) and biochemical tests. Dietary assessments can also be done by measuring what is eaten, converting this food into nutrients and comparing with nutrient reference values, this is relies a lot on recall, this can make it difficult to use.
What is the RDI and where can vitamins be found? What is fortification.
The recommended dietary intake tells us the rough amount we need of a nutrient per day and the amount a nutrient supply gives us can be found on the back of the packaging. Riboflavin, niacin and vitamin B12, (all of which are B vitamins), vitamin C, A , K and D do not have small amounts in many foods, the rest of the B vitamins though and vitamin E are found in small amounts in many foods. Fortification is done to some food sources to add these not easily found vitamins.
What do vitamins and minerals do?
Vitamins and minerals typically may act as coenzymes (organic carrier molecules) and cofactors (participate in the catalysis, can be non organic) but also play structural, antioxidant and DNA/RNA roles.
What are some of the functions of the vitamins?
B vitamins typically are involved in energy metabolism and act as coenzymes (vitamin B12 works with folate). Vitamin C is an antioxident and collagen cofactor, vitamin A has many functions e.g vision and protein synthesis, vitamin K is used in blood clotting, vitamin E is and antioxidant, Vitamin D maintains the blood calcium and Phosphorous levels.
What is thiamin used for and what does its deficiency lead to? How is it being deealt with?
thiamin is part of the co-enzyme thiamin pyrophosphat which acts to convert pyruvate to acetyl CoA (one carbon unit transfer) in the TCA cycle as well as a role in nerve cells. Deficiency leads to lack of glucose and increase in levels of pyruvate and lactate (vasodilation, venous pooling and oedema leading to heart failure (Beriberi) and cerebral beriberi and psychosis (Wernicke-Korsakoff). Deficiency is common in alcoholics and in order to counter it flour is fortified with thiamin in Straya and NZ.
