Nutrition Human Nutrition - The science of food, the nutrients and other substances contained therein, their action, interaction, and balance in relation to health and disease Normal Nutrition - caloric and nutrient requirements throughout the life cycle and for specific populations Clinical Nutrition - nutrition intervention aimed at the treatment or prevention of disease or illness 2
Nutrients Macronutrients Carbohydrates Proteins Fats Micronutrients Vitamins Minerals Others Fiber, water 3
Vitamins Organic substances essential for normal cell function, growth and development There are 13 essential vitamins They are grouped into 2 categories: fat-soluble and water-soluble Present in various foods and are available as dietary supplements 4
Vitamin Sources & Functions Vitamin A B-1 (Thiamine) Sources Cod liver oil, dairy products, sweet potatoes, carrots, leafy vegetables, and fortified foods such as breakfast Enriched, fortified, or whole-grain products, such as bread, pasta, and cereals. Helps the body process carbohydrates. Function Needed for good eyesight and normal functioning of the immune system Helps the body process carbohydrates B-2 Organ meats, breads, fortified cereals, almonds, asparagus, cooked eggs, dark meat chicken, and cooked beef Used in many body processes, such as converting food into energy. It also participates in the metabolism of many drugs and helps in the production of red blood cells B-3 3 (Niacin) Light-meat chicken, tuna, salmon, turkey, enriched flour, peanuts, and fortified cereals Aids in digestion and converting food into energy. Also used by the body to help make cholesterol B-6 Fortified cereals, fortified soy-based meat substitutes, baked potatoes with skin, bananas, light-meat chicken and turkey, eggs, and spinach B-12 Beef, clams, mussels, crabs, salmon, poultry, soybeans, and fortified foods Vital for a healthy nervous system. Helps the body break down proteins. Helps the body break down stored sugar Needed for creating red blood cells Reference: http://www.webmd.com/diet/vitamin-mineral-sources (2010) 5
Vitamin Sources & Functions Vitamin C (Ascorbic acid) D E Folate (Folic acid) K Sources Citrus fruits, red berries, tomatoes, potatoes, broccoli, cauliflower, brussels sprouts, red and green bell peppers, cabbage, and spinach Fortified milk, cheese, and cereals; egg yolks; salmon; and sunlight Leafy green vegetables, almonds, hazelnuts, and vegetable oils like sunflower, canola, and soybean Fortified cereals and grain products; lima, lentil, and garbanzo beans; and dark leafy vegetable Leafy green vegetables like parsley, chard, and kale; olive, canola, and soybean oils; and broccoli Function Helps promote a healthy immune system and is required to help make collagen, which holds cells together. It is also required for making chemical messengers in the brain Needed to process calcium and maintain bone health Functions as an antioxidant Vital for cell development, prevents birth defects, promotes heart health, and helps red blood cells form Helps clot blood and maintains bone health Reference: http://www.webmd.com/diet/vitamin-mineral-sources (2010) 6
Nutrient Requirement is based on: 1. Observed food intakes by healthy individuals expressed as recommended dietary allowance; intake meeting dietary requirements of 95% of individuals (RDA) 2. Genetic, developmental, lifestyle, environmental, normal aging, and pathologic conditions for any given individual, which may vary greatly from the RDA Am J Clin Nutr 2000;72(suppl):507S 11S. 7
Limitation of RDA It is based on normal distribution, thus it may not reflect the need of a certain segment of the population Average requirement Number of persons 2SDs RDA 5% of population Intake needed to meet requirement 8
Food label showing % Daily Value 9
Some reasons behind the use of individualized nutrient requirement: Nutrient in the diet may be inadequate due to low food intake A person s intake of nutrients may be dependent on RDA, but new scientific data indicates that such recommendations underestimate individual requirements Special conditions at a certain point in the person s life cause requirements to change without corresponding changes in diet. 10
REASON 1 Nutrients in the diet may be inadequate due to low food intake
Undernutrition is still a problem More than 1.02 B hungry people worldwide Neglect of agriculture Worldwide economic crisis Significant increase in food prices FAO Report (2009) 12
Vitamin and mineral deficiencies exist One out of 3 people in developing countries are affected by vitamin and mineral deficiencies, according to WHO (2009) Vitamin A Iron Iodine 13
Countries abundant in food have not eradicated vitamin & mineral deficiencies In 2002-03, 03, a study reported that Americans have inadequate intake of: Vitamin E (93%) Magnesium (56%) Vitamin A (44%) Vitamin C (31%) What We Eat in America Report USDA 2005 14
A study of fast food restaurant use among 4746 adolescents: associations with nutrient intake, food choices and behavioral and psychosocial variables revealed that 15
Frequency of fast food restaurant use was Positively associated with intake of total energy, percent energy from fat, daily servings of soft drinks, cheeseburgers, french fries and pizza Inversely associated with daily servings of fruit, vegetables and milk Positively associated with student employment, television viewing, home availability of unhealthy foods, and perceived barriers to healthy eating International Journal of Obesity (2001) 25, 1823 1833 16
Inadequate intake of nutrients among specific segments of population did exist Vitamin B6 for women > 50 y/o Zinc for males and females >70 y/o Only about half of women aged 9-9 18 y/o has adequate intake of phosphorus What We Eat in America Report USDA 2005 17
Fruit & vegetable consumption in many countries has decreased Food consumption surveys showed low consumption of fruits and vegetables in many regions of the developing world. At present, only a small and negligible minority of the world s population consumes the generally recommended high average intake of fruits and vegetables. In 1998, only 6 of the 14 WHO regions had an availability of fruits and vegetables equal to or greater than the earlier recommended intake of 400 g per capita per day. World Health Organization Technical Report Series No. 916 (2003) 18
Also The stress resulting from demanding jobs and having Type A personality are contributory to the lack of attention given to the food being taken in. The proliferation of fast food chains and ready-to to-cook quick meals becomes an easy alternative to well-thought of meals. Meal planning belongs to the health conscious few. 19
REASON 2 A person s intake of nutrients meet RDA, but new scientific data indicates that such underestimate individual requirements 20
Examples Need for increased folic supplementation for women of reproductive age starting three months prior to conception to prevent NTD and other congenital anomalies. High incidence of Vitamin D deficiency among pregnant women in Australia & NZ. Higher requirement for those with limited sun exposure. J Obstet Gynaecol Can 2007;29(12):1003 1013 RANZCOG College Statement: C-Obs 25 (2008) 21
REASON 3 There are special conditions at different points in life requiring amounts of nutrients higher than RDA 22
Genetic Factor Hyperhomocysteinaemia is the commonest of the thrombophilias with approximately 1.5% of the population being homozygous for the MTHFR mutation and 25% heterozygous. The thrombophilic tendency is minimised by an adequacy of folate, riboflavin, B6 and B12. Royal Australian and New Zealand College of Obstetricians and Gynecologists College Statement: C-Obs 25 (2008) 23
Developmental Factors Infancy Childhood Adolescence Pregnancy Lactation Aging 24
Example Adolescents, particularly girls, are especially vulnerable to iron deficiency due to low intake and absorption of iron, and increased iron requirements for growth and replacement of menstrual blood losses. Anemia can be associated with other nutrient deficiencies (folic acid, vitamin A, B 12) Adolescent Nutrition: A Review of the Situation in Selected South-East Asian Countries (2001) 25
Lifestyle Choices Reduced intake of dietary fat Reduces absorption of fat-soluble vitamins Engagement in sports High oxygen demand on blood requiring B vitamins Need for preventing oxidative damage to cellular and subcellular structure and function during exercise requiring antioxidant vitamins Smoking Oxidative damage and depletion of endogenous antioxidants 26
Lifestyle Choices Vegetarianism Vegans on fad require Vitamin B12 usually lacking in their diet Obesity Imbalance in nutrient intake Excessive Coffee drinking Calcium depletion 27
Aging Major structural, functional and metabolic changes Decreased stomach acid and intestinal blood flow affecting breakdown & absorption of Vitamin B12 Decrease in hormone production, etc. Modification of vitamin requirements Postmenopausal women Presence of multiple diseases Intake of multiple medicines Cognitive decline 28
Pathologic Nutrient Vitamin D Multivitamins Vitamin B-6, Folate, and Vitamin B-12 Folic Acid Vitamin A Various vitamins Condition/ Disease Multiple sclerosis, osteoporosis, cardiovascular conditions HIV survival Symptoms of depression Several forms of cancer -colorectum, breast, ovary, pancreas, brain, lung and cervix Pulmonary tuberculosis Surgery, injury, recovery, rehabilitation * In addition to various deficiency conditions emanating from inadequate intake and disturbed metabolism 29
Is there really a need for vitamin supplementation? 30
A supplement has benefit only when the normal intake of a bioavailable form of a nutrient is lower than the amount that would provide maximum benefit as judged from all biological perspectives. To be efficacious, dietary supplements must either provide a nutrient that is normally undersupplied to cells or exert a pharmacologic effect on cellular processes. (Steven Seizel 2000) Am J Clin Nutr 2000;72(suppl):507S 11S. 31
Metabolic, environmental, and genetic factors can make individual nutrient requirements differ from the estimated needs calculated from population-based data. Am J Clin Nutr 2000;72(suppl):507S 11S. 32
Is intake sufficient? Higher Requirement? Life Cycle Optimal Function Risk reduction Pharmacologic Environment Lifestyle Is there a scientific basis to increase intake? Can intake be achieved from Food? NO Use Supplement AN APPROACH TO DIETARY SUPPLEMENTATION Adapted from Seizel, S. Am J Clin Nutr 2000;72(suppl):507S 11S. 33
Conclusions Food is still the best source of vitamins and other nutrients There are factors which affect nutrient requirement of an individual There are valid reasons for vitamin supplements as long as they are backed up by scientific evidences Too much vitamin intake is equally as dangerous as lack of intake Pharmacists have a role to play in the use of vitamin supplements 34
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