Option A: Human nutrition and health

Option A: Human nutrition and health

Define nutrient. A Nutrient is a chemical substance found in foods that is used in the human body. http://www.faqs.org/nutrition/images/nwaz_02_img0168.jpg

List the type of nutrients that areessential in the human diet: Amino acidsare the building blocks of protein . The body has twenty different amino acids that act as these building blocks. Nonessential amino acids are those that the body can synthesize for itself, provided there is enough nitrogen, carbon, hydrogen, and oxygen available. Essential amino acids are those supplied by the diet , since the human body either cannot make them at all or cannot make them in sufficient quantity to meet its needs. Under normal conditions, eleven of the amino acids are nonessential and nine are essential.

Fatty Acids Saturated fatty acids can align closely together so lipids containing primarily saturated fatty acids are usually solid at room temperature (aka Fat). The C=C double bond(s) in unsaturated fatty acids causes the molecule to "bend" (a fatty acid with one C=C bond is mono-unsaturated, a fatty acid with several C=C bonds is poly-unsaturated. Because they are "bent", unsaturated fatty acids are less able to interact and lipids contain primarily unsaturated fatty acids are liquid at room temperature (oils).

Trans fatty acids are manufactured fats created during a process called hydrogenation, which is aimed at stabilizing polyunsaturated oils to prevent them from becoming rancid and to keep them solid at room temperature. They may be particularly dangerous for the heart and may pose a risk for certain cancers. Hydrogenated fats are used in stick margarine, fast foods, commercial baked goods (donuts, cookies, crackers), processed foods, and fried foods. Cis and trans are terms that refer to the arrangement of chains of carbon atoms across the double bond. In the cis arrangement, the chains are on the same side of the double bond, resulting in a kink. In the trans arrangement, the chains are on opposite sides of the double bond, and the chain is straight.

Omega-3 fatty acids are a form of polyunsaturated fat that the body derives from food. Omega-3s (and omega-6s) are known as essential fatty acids (EFAs) because they are important for good health. The body cannot make these fatty acids on its own so omega-3s must be obtained from food. These different types of acids can be obtained in foods such as cold-water fish including tuna, salmon, and mackerel. Other important omega 3 fatty acids are found in dark green leafy vegetables, flaxseed oils, and certain vegetable oils. • Omega-3 fatty acids have been found to be beneficial for the heart. Positive effects include anti-inflammatory and anti-blood clotting actions, lowering cholesterol and triglyceride levels, and reducing blood pressure. These fatty acids may also reduce the risks and symptoms for other disorders including diabetes, stroke, rheumatoid arthritis, asthma, inflammatory bowel disease, ulcerative colitis, some cancers, and mental decline.

Minerals These foods are all “mineral dense” foods. Find out which minerals are in each food. http://hachten.com/monavie/wp-content/images/19-fruits.jpg

Vitamins A vitamin is an organic compound required as a nutrient in tiny amounts by an organism http://www.childrenfirst.nhs.uk/teens/images/healthyeating/vitamins.jpg

This might be a useful table to help you fill in the Minerals lists. http://www.healthalternatives2000.com/minerals-nutrition-chart.html

Make a table!

Water

Roughage / Fibre Consists mainly of Cellulose which is insoluble and indigestible by animals. Forms bulk which allows the gut to move the food. Not enough fibre causes constipation in the short term, and may lead to spastic colon in long term and cancers of the gut due to build up of poisons. Go once a day! Good sources: Fruit and vegetables. http://fitness.resourcesforattorneys.com/images/dietary-fiber.jpg

Outline the consequences of proteindeficiency malnutrition. • Protein deficiency is shortage of one or more essential amino acids. • The consequences are lack of blood plasma proteins and subsequent tissue fluid retention, with swelling of the abdomen. • Development of children is likely to be both mentally and physically retarded.

Kwashiorkor – a protein deficiency • Kwashiorkor is a condition that affects children who belong to areas that have experienced shortage of food. This is usually places where famine has struck. Among the lesser educated classes of society also Kwashiorkor is a fairly common problem since the lack of awareness about a balanced diet often leads to a an inadequate consumption of proteins.

Explain the causes and consequencesof phenylketonuria (PKU) and howearly diagnosis and a special diet canreduce the consequences. • Phenylketonuria (PKU) is an autosomal recessive genetic disorder characterized by a deficiency in the hepatic enzyme phenylalanine hydroxylase (PAH) This enzyme is necessary to metabolize the amino acid phenylalanine ('Phe') to the amino acid tyrosine. When PAH is deficient, phenylalanine accumulates and is converted into phenylpyruvate (also known as phenylketone), which is detected in the urine.

It can be managed by a patient controlling their diet with little or no side effects, just inconvenience with managing the treatment. If however the condition was left untreated, it can cause problems with brain development, leading to progressive mental retardation, brain damage, and seizures. • There is currently no cure for this disease, although some treatments are available with varying success rates. PKU is generally detected through newborn screening.

Evaluate the health consequencesof diets rich in the different types offatty acid. • Dietary studies are difficult to control sufficiently to gain really reliable data. Where data are produced it may not be possible to conclude causal relationships from correlation. Care must be taken to think critically about nutrition-based news stories and articles.

Distinguish between minerals andvitamins in terms of their chemicalnature. • Minerals are elements in ionic form. • Vitamins are organic compounds.

Outline two of the methods that have been used to determine the recommended daily intake of vitamin C. • Some of the experiments used to determine necessary levels of vitamin consumption were done using conscientious objectors during the second world war. This raises ethical questions about trials in which the experimental subjects could be harmed or suffer. Look at this website for detailed description of what they did! It is fascinating. http://ije.oxfordjournals.org/cgi/content/full/35/3/556

During World War II, 36 conscientious objectors participated in a study of human starvation conducted by Ancel Keys and his colleagues at the University of Minnesota. The Minnesota Starvation Experiment, as it was later known, was a grueling study meant to gain insight into the physical and psychologic effects of semistarvation and the problem of refeeding civilians who had been starved during the war. During the experiment, the participants were subjected to semistarvation in which most lost >25% of their weight, and many experienced anemia, fatigue, apathy, extreme weakness, irritability, neurological deficits, and lower extremity edema. In 2003–2004, 18 of the original 36 participants were still alive and were interviewed. Many came from the Historic Peace Churches (Mennonite, Brethren, and Quaker), and all expressed strong convictions about nonviolence and wanting to make a meaningful contribution during the war. Despite ethical issues about subjecting healthy humans to starvation, the men interviewed were unanimous in saying that they would do it all over again, even after knowing the suffering that they had experienced. After the experiment ended, many of the participants went on to rebuilding war-torn Europe, working in the ministries, diplomatic careers, and other activities related to nonviolence.

Life magazine photograph of conscientious objectors during starvation experiment. July 30, 1945. Volume 19, Number 5, p. 43. Credit: Wallace Kirkland/Time Life Pictures/Getty Images

Animal trials on Vitamin C • Guinea pig trials: observed the effect of vitamin C concentration on collagen structure. After periods of varying vitamin C supplementation and measurement of blood and urine vitamin C levels, guinea pigs were sacrificed and the structure of collagen fibres observed. Guinea pigs with restricted vitamin C showed weaker collagen. • Think ethics! What is vivisection? Can it be justified? http://www.woodwindsanimalhotel.com/images/guinea-pig.jpg

What is rebound malnutrition? • Rebound malnutrition can occur when a normally adequate intake of a vitamin follows a period of excessive intake and excretion.

List the sources of vitamin D in human diets. • Vitamin D can be produced by skin as a response to sunlight.It also can be found (in a slightly different form) in foods: fatty fish, fish oils, liver, eggs and some mushrooms. In some countries, milk is supplemented with vitamin D.

Now using your food diary….. Go to http://nutritiondata.self.com/ • For the 24 hours you recorded in homework do a diet analysis. • Make up an ‘ideal’ MacDonalds Day diet, of breakfast, lunch afternoon snack and dinner. Each meal must be different! Answer the following questions: • What was your diet good for? • What mineral, vitamin or other nutrient was lacking in your diet? • What suggestions could you make to improve your diet?

Option A: Human nutrition and health