Background Chemical exposures have been associated with a variety of health effects; however, little is known about the global disease burden from foodborne chemicals. Food can be a major pathway for the general population’s exposure to chemicals, and for some chemicals, it accounts for almost 100% of exposure.  Methods and Findings Groups of foodborne chemicals, both natural and anthropogenic, were evaluated for their ability to contribute to the burden of disease.  The results of the analyses on four chemicals are presented here - cyanide in cassava, peanut allergen, aflatoxin, and dioxin.  Systematic reviews of the literature were conducted to develop age- and sex-specific disease incidence and mortality estimates due to these chemicals.  From these estimates, the numbers of cases, deaths and disability adjusted life years (DALYs) were calculated.  For these four chemicals combined, the total number of illnesses, deaths, and DALYs in 2010 is estimated to be 339,000 (95% uncertainty interval [UI]: 186,000-1,239,000); 20,000 (95% UI: 8,000-52,000); and 1,012,000 (95% UI: 562,000-2,822,000), respectively.  Both cyanide in cassava and aflatoxin are associated with diseases with high case-fatality ratios.  Virtually all human exposure to these four chemicals is through the food supply.  Conclusion Chemicals in the food supply, as evidenced by the results for only four chemicals, can have a significant impact on the global burden of disease. The case-fatality rates for these four chemicals range from low (e.g., peanut allergen) to extremely high (aflatoxin and liver cancer).  The effects associated with these four chemicals are neurologic (cyanide in cassava), cancer (aflatoxin), allergic response (peanut allergen), endocrine (dioxin), and reproductive (dioxin).

Analyses have been made for crude protein, amino acids, and trypsin inhibitor content of 21 cultivars of sweet potato collected from two regions of the highlands of Papua New Guinea, one (Upper Mendi region) of high incidence of Enteritis necroticans (EN) and the other (Erave region) of low incidence of EN. The incidence of EN occurs in populations that are reported to be low in protein; hence, the analysis of the staple food (sweet potato) may give a clue to the difference between the two regions. No significant differences were found in the crude protein content, amino acid scores, or trypsin inhibitor contents between the sweet potatoes from the two regions. The range of crude protein content is 0.5-2 g of protein/100 g of fresh sweet potato; the S-containing amino acids (cystine plus methionine) are limiting in 65% of cases, followed by lysine (23%), leucine (6%), and other amino acids. The average chemical score is 0.6. The trypsin inhibitor content varies greatly over a 67-fold range. No significant correlation (r = 0.057) is found between trypsin inhibitor and crude protein.

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Policy on fluoride intake involves balancing caries against dental fluorosis in populations. The origin of this balance lies with Dean's research on fluoride concentration in water supplies, caries, and fluorosis. Dean identified cut points in the Index of Dental Fluorosis of 0.4 and 0.6 as critical. These equate to 1.3 and 1.6 mg fluoride (F)/L. However, 1.0 mg F/L, initially called a permissible level, was adopted for fluoridation programs. McClure, in 1943, derived an "optimum" fluoride intake based on this permissible concentration. It was not until 1944 that Dean referred to this concentration as the "optimal" concentration. These were critical steps that have informed health authorities through to today. Several countries have derived toxicological estimates of an adequate and an upper level of intake of fluoride as an important nutrient. The US Institute of Medicine (IOM) in 1997 estimated an Adequate Intake (AI) of 0.05 mg F/kg bodyweight (bw)/d and a Tolerable Upper Intake Level (UL) of 0.10 mg F/kg bw/d. These have been widely promulgated. However, a conundrum has existed with estimates of actual fluoride intake that exceed the UL without the expected adverse fluorosis effects being observed. Both the AI and UL need review. Fluoride intake at an individual level should be interpreted to inform more nuanced guidelines for individual behavior. An "optimum" intake should be based on community perceptions of caries and fluorosis, while the ultimate test for fluoride intake is monitoring caries and fluorosis in populations.

In Australia, the process by which food energy factors are derived for food labelling purposes is under review. One of the questions of international relevance is whether energy factors should be derived using a definition of metabolisable energy (ME) or a definition of net (metabolisable) energy (NME), or some mixture of the two. ME describes the food energy available for heat production and body gains. NME deducts obligatory thermogenesis from ME in an attempt to reflect the food energy that can be converted to ATP energy within the body. Some countries use NME to derive energy factors for novel food ingredients such as sugar alcohols and polydextrose, but continue to use ME for protein, fat, carbohydrate, and alcohol. The present paper puts a case for using a consistent system (ME at the present time) for all food components. Reasons for this include: consistent application to all food components allows valid comparisons between products; food energy values and estimates of energy expenditure (food energy requirements) should be directly comparable; NME does not account for all sources of thermogenesis; differences between ME and NME for sugar alcohols and polydextrose are small in the context of the whole diet; and the ME system does not preclude information about metabolic efficiency being provided as additional information. Any major change to the way in which energy values are expressed (e.g. global adoption of the NME system) merits wide discussion among the human nutrition community. One aim of this present paper is to stimulate this discussion.Energy factors: Food labelling: Metabolisable energy: Net (metabolisable) energyThe energy value of foods is an important issue for consumers (who may be concerned about energy intakes for body weight management), for industry (for product development and labelling) and for the scientific community and health professionals (for educational, clinical and experimental applications).In Australia, the process by which energy factors for food components are derived for food labelling purposes is under review (Australia and New Zealand Food Authority, 1999). This was prompted by a lack of clear definition of how currently prescribed energy factors were derived, and lack of guidance for establishing factors for novel food components. The key questions posed were: (1) whether energy factors should be derived using a definition of metabolisable energy (ME) or net (metabolisable) energy (NME); and (2) whether energy factors should be derived in a consistent fashion for all food components. The answers to these questions have international relevance.The consistent application of the ME system is contrary to the use by some countries of ME for conventional nutrients and NME for polyols and polydextrose, while the NME system is not consistently applied anywhere in the world. The present paper puts a case for using a consistent approach to derive energy factors for all food components, conventional and novel, and for using ME as the basis of derivation at the present time. The...