1. Chapter 1.3: General Concepts on Food, Nutrition and Food Safety We all eat and exercise to stay alive, to enjoy the taste of food and to socialise Economic and social differences in various parts of the world lead to problems for food security and food safety For example, insufficient food intake in poorer parts of the world can lead to protein-energy malnutrition, which may be associated with micronutrient deficiencies and disease e.g. iron, Vit A deficiency. Obesity, elevated blood pressure, cardiovascular disease and diabetes are now a major problem in developed parts of the world. Specific lifestyle factors also impact food chemical risk assessment and safety. 1

2. General Concepts…….(Cont’d) Human beings have nutritional requirements and therefore food intakes that depend on the level of physical activity But we are all different! Other factors – age, sex, pregnancy and general health status play a role E.g. Men up to 60yrs and 76kg – approx. 0.16 Mj/kg BW/day energy requirement with limited physical activity and 0.18 Mj/kg BW/day for active lifestyle E.g. Women up to 60yrs and 62kg – approx. 0.15 Mj/kg BW/day for active lifestyle; 0.14Mj/kg BW/day for decreased activity and age 61-74yrs BUT children : -6-9 months – approx. 0.35Mj/kg BW/day 2-5yrs – approx. 0.33Mj/kg BW/day 6-9yrs – approx. 0.31Mj/kg BW/day Note: 1 Mj = 238 nutritional calories 2

3. Lifestyle Factors and Impacts on Risk Assessment The more widespread the greater the impact – e.g. different diets, hobbies and sports, lifestyle factors such as tobacco smoking and alcohol consumption will have an important influence on the risk assessment and need to be identified clearly. The diet of the specific population should be taken into account with regard to toxicity and exposure stages of the risk assessment. EXAMPLE: Interactions between toxic metals and essential metals from the diet can affect the risk of toxicity. Absorption of toxic metals from the lung and GI tract may be influenced by the presence of an essential metal or trace element if the toxic metal shares the same homeostatic mechanism. Lead and calcium, and cadmium and iron are examples. 3

4. Lifestyle Factors and Impacts on Risk Assessment…..(Cont’d) EXAMPLE: Other dietary interactions include an inverse relationship between protein content of the diet and cadmium and lead toxicity. EXAMPLE: Vitamin C in the diet also reduces lead and cadmium absorption. EXAMPLE: Different types of food will have different amounts of chemical (and microbiological) agents and hence cause a range of toxic effects depending on dietary habits. EXAMPLE: the major pathway of exposure to many toxic metals in children is food, and children consume more kilojoules/kg of body weight than adults do. Furthermore, children have a higher gastrointestinal absorption of metals, particularly lead. 4

5. Lifestyle Factors and Impacts on Risk Assessment…..(Cont’d) EXAMPLE: Alcohol ingestion may influence toxicity indirectly by altering diet and reducing essential mineral intake. The ingestion of alcoholic beverages (ethanol), fats, protein, calories and aflatoxins has been implicated in carcinogenesis (Klaassen, 1996). EXAMPLE: Home grown produce such as vegetables has been associated with contamination of heavy metals such as lead, arsenic and cadmium. EXAMPLE: Free-range poultry tissue (meat, fat, skin) and eggs (egg yolk) has been associated with contamination by organochlorine pesticides such as Aldrin, dieldrin and DDT and hence consumption of these foods can lead to increased exposure to these agents (Cross and Taylor, 1996). 5

6. Lifestyle Factors and Impacts on Risk Assessment…..(Cont’d) EXAMPLE: The type of diet can also influence the risk to exposure to hazardous chemicals. Vegetarians may have a reduced exposure to zinc. EXAMPLE: Individuals who consume barbecued foods can be exposed to relatively large amounts of PAHs from the cooking process (especially if food is smoked) EXAMPLE: Populations who consume seafood may be exposed to heavy metals such as mercury in fish and zinc in shellfish (e.g. oysters). 6

7. That We Are All Different Affects Chemical Safety So far we have learned that : Humans are different and have different nutritional status and food consumption needs depending on a variety of factors including age, sex, weight, physical activity, lifestyle factors etc Food contains chemicals that can be naturally occurring or added, wanted and unwanted. Chemicals have intrinsic hazards and some chemicals are toxic at certain concentrations. Some chemicals provide essential nutrition but some chemicals (naturally occurring, added, unwanted) in food can constitute a food safety risk depending on the intrinsic hazard of the chemical and the dietary exposure to the chemical. Chemical risk assessment is needed to deal with the possible negative influences of chemical compounds on our health and how to reduce/avoid these by combined clever use of risk assessment, risk management and risk communication. 7

8. Food Chemical Risk Assessment Gathers and Organises Information and Enables…. Risks at a point in time (including baseline risks) and changes in risk over time to be estimated and whether action is necessary Health Guidance Values to be estimated for food chemical hazards that can be used and which will adequately protect public health Assessments of new types of food chemical risk Assessments of different types of food chemical risks A comparison of the potential health impacts of various food chemical health-related interventions (thus enabling cost- effectiveness estimates) The identification and comparison of different factors that affect the nature and magnitude of the risk 8

9. Food Chemical Risk Assessment Gathers and Organises Information and Enables….(cont’d) Risk-based standards setting for regulatory exposure limits, and clean-up standards Prioritising issues according to their level of risks Questionable theories, methods and data to be challenged and addressed by providing a clearly documented and open process Risk-based food safety policy-making; and Consistent, transparent appraisal and recording of public health risks 9