A1: Components of the human diet Part2... Do we really know what we eat?????

Amino Acids Some amino acids are considered essential but others can be synthesized in our bodies. Of the 20 amino acids needed in the human diet, 9 of them are considered essential. They cannot be synthesized because the human genome lacks the necessary DNA sequences Examples of essential amino acids are valine and phenylalanine.

Fatty Acids = FATS Name Diagram of structure Description of structure Foods that contain them Health implications Saturated fatty acids Without double bonds Meats, dairy products, few vegetable oils Not heart healthy: raise LDL (bad cholesterol) Cis unsaturated fatty acids Double bonds, H are on the same side of the double bond Natural occuring. Ex.: omega 3 fatty acids Healthy Trans unsaturated fatty acids Double bonds, H are on different sides of the double bond Man-made: hydrogenated fat products Raise LDL and lower HDL (good cholesterol) Mono unsaturated fatty acids One double bond nuts, avocados, olives Heart-healthy: lower LDL and raise HDL Poly unsaturated fatty acids Two or more double bonds. Differences between the different structures of fatty acids A.1.6 Outline the variation in the molecular structure of fatty acids, including saturated fatty acids, cis and trans unsaturated fatty acids, monounsaturated and polyunsaturated fatty acids.

A.1.7 Evaluate the health consequences of diets rich in the different types of fatty acid.

A.1.8 Distinguish between minerals and vitamins in terms of their chemical nature. Minerals Vitamins

Water Water is needed for all metabolic process in the human body. Although it has no caloric value it is essential to the proper functioning of our bodies.

A.1.9 Outline two of the methods that have been used to determine the recommended daily intake of vitamin C.

A.1.10 Discuss the amount of vitamin C that an adult should consume per day, including the level needed to prevent scurvy, claims that higher intakes give protection against upper respiratory tract infections, and the danger of rebound malnutrition.

A.1.12 Discuss how the risk of vitamin D deficiency from insufficient exposure to sunlight can be balanced against the risk of contracting malignant melanoma. A.1.11 List the sources of vitamin D in human diets.

A.1.13 Explain the benefits of artificial dietary supplementation as a means of preventing malnutrition, using iodine as an example. Artificial dietary supplementation is the addition of a dietary supplement into the diet of an individual to prevent a deficiency of that particular nutrient and thus malnutrition. Artificial Dietary Supplementation In 1990, a campaign was started to eliminate IDD by adding it in small quantities to salt sold for human consumption.

A.1.14 Outline the importance of fibre as a component of a balanced diet.

REVIEW QUESTIONS 1.Distinguish between the chemical structure of Vitamins and Minerals – use Page of your text book. 2.What does RDI stand for? 3.What is the older method for calculating RDI? 4.What is the more modern method? 5.How much Vitamin C is needed to “saturate” the body? What happens to any excess? 6.What are the benefits and dangers / adverse effects of taking more than the RDI of Vitamin C? (Give details)