Nutrient Recommendations

Nutrient Recommendations NOTE: This topic has a three-part lecture. View each lecture and complete the guided notes. Part 1: Nutrient Requirements a) Nutrient Needs We all need the same nutrients, but not in the same amounts. - Six key nutrients o macronutrients: carbohydrates, proteins and fats o micronutrients: minerals and vitamins and water - The amounts needed vary among people based on such factors as o Age o Body size o Gender o Genetic traits (difficult to measure) o Growth status (pregnant, infant, puberty) b) Nutrient Target Range 1 Optimal intake range is set as the intake at which the human body functions best. - Poor nutrition results from an intake that is either too high or too low relative to optimal levels. - Intake on either side of this optimal range results in impaired bodily function. - Poor nutrition can initiate diseases. c) Nutrient Target Range 2 RDA - recommended dietary allowance UL - tolerable upper intake level - Below the RDA the intake becomes progressively deficient. - Above the UL the intake becomes progressively excessive. - Between the RDA and the UL is the optimal intake. d) Nutrient Deficiencies Nutrient deficiencies occur when we consume essential nutrients less than the recommended dietary allowance (RDA). If we consume these nutrient deficiencies for a prolonged period of time, we begin to see physical signs that could become permanent. Correcting the intake prevents prolong dietary deficiency. e) Nutrient Toxicities Consuming a nutrient in an excessive amount (above the UL) oversupplies cells upsetting the balance which may cause toxicity diseases. - if you consume an excessive amount iron over a long period time, the iron could be deposited into organs and cause death. f) Your Health is in the Balance - Between the RDA and the UL is a healthy balance - Vitamin A toxicity results from over consumption of preformed vitamin A (tablet of vitamin A or from animal sources) - plant sources of vitamin A (beta-carotene) do not have the same results. g) Adaptive Mechanisms 1 The body has adapted mechanisms to manage small changes in our diet such as consuming inadequate or excessive supplies in small quantities over short periods of time. - If a nutrient supply is very low, the body may adapt by conserving that nutrient and not releasing it or excreting it. - If a nutrient is very high, the body will try to eliminate it more aggressively than it might normally. h) Adaptive Mechanisms 2 Excesses can be stored Dietary surpluses of energy and some nutrients stored in tissues for later use. - If the body senses that food being consumed has a surplus of a certain nutrient and tissues are not full of that nutrient then the body can store it for later use. - Iron, vitamin A, B12 and calcium can be stored. Absorption can be modified - The body can also sense how much of a nutrient it has and modify its absorption based on its needs. - Body’s nutrient absorption dependent on body’s need - Two people can eat the same meal. If person A has low storage of iron and person B has a high storage of iron, then person A will absorb more iron out of the meal (iron and Ca) Excesses can be eliminated - Body has low storage capacity for some nutrients and excesses are eliminated through urine or stools. - Vitamin C and water. - Increased water consumption will result in increased urination and aid body mechanisms in managing changes in our diet when too little or a too much of a nutrient is consumed. i) Summary - We all need the same six key nutrients to be supplied to support health. - Nutrient needs vary depending on age, gender, genetics and growth status. - Too little or too much of any nutrient causes impairment to health. The human body has adaptive mechanisms to deal with short-term inadequacy or excessive supply of a nutrient. Part 2: The Dietary Reference Intakes (DRI) a) DRI The Dietary Reference Intakes (DRI) are a comprehensive set of nutrient reference values for a healthy population that can be used for assessing and planning diet. A Dietary Reference Intake has been published since 1997 and replaced previously published recommended nutrient intakes or the RNIs. They are established by Canadian and American scientists through a review process overseen by the US National Academies which is an independent non-governmental body. The DRIs reflect the current state of scientific knowledge with respect to nutrient requirements and are published as a series of reports by the US National Academies. b) Goals of the DRI Committee Since 1938 Health Canada has been reviewing nutrition research regularly and defining nutrient needs for healthy people. The goals of this committee are to develop nutrient recommendations based on the latest scientific evidence. Recommendations: - Apply to healthy persons only - Are designed to prevent o Deficiency disorders o Chronic diseases o Cancer o Heart disease o Osteoporosis o Not for the restoration of health or repletion of nutrients in those with deficiencies c) Excesses to DRIs When researchers were developing the DRIs, they had to take into consideration a new phenomenon where individuals were causing potential adverse risk effects to their health based on excessive intake of nutrients due to supplements and/or fortified food consumption. d) Nutrient Recommendations DRIs are nutrient reference values that are indicators of good health and prevention of chronic disease. The DRI committee has set recommended intakes for all 6 key nutrients, how much water we should be consuming and overall how much energy would be essential for optimal health. - Macronutrients o Carbohydrate [including fibre] o Fat [including essential fatty acids] o Protein - Micronutrients o Vitamins o Minerals o Water o Energy e) Acceptable Macronutrient Distribution Range (AMDR) - Healthy ranges of intake for carbohydrate, fat and protein - reduced risk of chronic disease while providing adequate intakes of essential nutrients Acceptable Macronutrient Distribution Range (AMDR) Percent of calories from: Age group Carbohydrates Protein Fat 1–3 yrs 45–65% 5–20% 30–40% 4–18 yrs 10–30% 25–35% 19 yrs + 10–35% 20–35%