Risk analysis applied to food fortification

OBJECTIVE

To describe how a risk analysis can be applied to food fortification, with emphasis on voluntary fortification and intake levels that might exceed usual dietary levels.

DESIGN

Use of the risk analysis model as a frame to classify nutrients according to the risk of exceeding upper safe intake levels. Furthermore, to apply the model when discussing possible consequences of liberal fortification practices on eating behaviour and disease patterns.

SETTING

The discussion on food fortification presently going on internationally.

RESULTS

Micronutrients can be classified according to their safety margin, i.e. the size of the interval between the recommended intake and the upper safe level of intake. We suggest that nutrients with a small safety margin, i.e. for which the upper safe level is less than five times the recommended intake, be placed in a category A and should be handled with care (retinol, vitamin D, niacin, folate and all minerals). Category B comprises nutrients with an intermediate safety margin (vitamins E, B6, B12 and C), while nutrients that according to present knowledge are harmless even at 100 times the recommendation (vitamin K, thiamin, riboflavin, pantothenic acid and biotin) are categorised as C.

DISCUSSION

The risk analysis model is a useful tool when assessing the risk of both too low and excess intakes of single micronutrients, but can also be applied to analyse the consequences of fortification practices on eating behaviour and disease patterns. Liberal fortification regulations may, for example, distort the conception of what is healthy food, and drive consumption towards a more unhealthy diet, contributing to the plague of overweight and concomitant increased risk of degenerative diseases.

CONCLUSION

The impact of fortification practices on the total eating pattern of a population should become an integrated part of the discussions and regulations connected to the issue.

[Antioxidant micronutrients and cataract. Review and comparison of the AREDS and REACT cataract studies]

Age-related cataract remains the major cause of preventable blindness throughout the world. It has long been realized that one of the important etiological factors for this disease is oxidative and in particular photooxidative damage to the lens. Therefore, the antioxidant micronutrients, vitamins C and E and the carotenoids, in particular beta-carotene, have been discussed as factors that could reduce the risk for this disease. The present article reviews what is known about the transport of these substances to the lens, their accumulation, and their concentrations in the lens. Furthermore, the available epidemiological literature is briefly mentioned, but more emphasis has been placed on a description and discussion of major clinical intervention studies. Finally, the design and results of two of those trials using antioxidant micronutrients, the Age-Related Eye Disease Study (AREDS) and the Roche European American Cataract Trial (REACT), are compared. The AREDS trial did show a positive effect only for age-related macular degeneration but not for cataract, while the REACT trial demonstrated a small but statistically significant deceleration of cataract progression. The techniques for following the course of a cataract in the REACT study were more sensitive to subtle changes than those used in the AREDS study, and this may have been one important factor accounting for the differences. The authors' detailed comparison of these studies, however, suggests that even more important may have been the fact that in the REACT study intervention started earlier in the disease process,with higher doses of vitamins C and E and beta-carotene and consequently with larger plasma concentrations of these antioxidant micronutrients. The REACT trial results support the early complementation of a diversified diet with supplements containing vitamins C and E and beta-carotene as well as other carotenoids. The authors also believe that it is reasonable to include these micronutrients in the therapeutic armamentarium of general ophthalmological practice.

[Is a cataract avoidable? Current status with special emphasis on the pathophysiology of oxidative lens damage, nutritional factors, and the ARED study]

The benefit of long-term nutrient intake to reduce the risk of age-related ocular disease such as cataract or macular degeneration is subject to controversy. Conclusions about the benefits and risks of antioxidant supplements can be expected after reviewing the current literature concerning oxidative-induced lens damage and nutritional effects. Identification of influenceable risk factors for senile cataracts could achieve immense economical relevance. In contrast to former longitudinal epidemiological studies, the AREDS report failed to verify protective properties of highly concentrated vitamin supplements on cataract formation. Although there are enough epidemiological indications for reducing the risk of cataracts by the intake of antioxidants, a general recommendation for the use of supplements is untimely or even wrong until stringent evidence of efficacy is provided. The usefulness of cataract prevention is discussed.

Hazard characterisation of chemicals in food and diet. dose response, mechanisms and extrapolation issues

Hazard characterisation of low molecular weight chemicals in food and diet generally use a no-observed-adverse-effect level (NOAEL) or a benchmark dose as the starting point. For hazards that are considered not to have thresholds for their mode of action, low-dose extrapolation and other modelling approaches may be applied. The default position is that rodents are good models for humans. However, some chemicals cause species-specific toxicity syndromes. Information on quantitative species differences is used to modify the default uncertainty factors applied to extrapolate from experimental animals to humans. A central theme for extrapolation is unravelling the mode of action for the critical effects observed. Food can be considered as an extremely complex and variable chemical mixture. Interactions among low molecular weight chemicals are expected to be rare given that the exposure levels generally are far below their NOAELs. Hazard characterisation of micronutrients must consider that adverse effects may arise from intakes that are too low (deficiency) as well as too high (toxicity). Interactions between different nutrients may complicate such hazard characterisations. The principle of substantial equivalence can be applied to guide the hazard identification and hazard characterisation of macronutrients and whole foods. Macronutrients and whole foods must be evaluated on a case-by-case basis and cannot follow a routine assessment protocol.

COMT genotype, micronutrients in the folate metabolic pathway and breast cancer risk

Catechol-O-methyltransferase (COMT) catalyzes the O-methylation of catechol estrogens (CEs), using S-adenosylmethionine (SAM) as a methyl donor. Several studies have indicated that the val108met COMT polymorphism, which results in a 3-4-fold decrease in activity, is associated with increased breast cancer risk. Folate, whose intake levels have also been associated with breast cancer risk, and other micronutrients in the folate metabolic pathway influence levels of SAM and S-adenosylhomocysteine (SAH), a COMT inhibitor generated by the demethylation of SAM. Because these micronutrients have been shown to alter SAM and SAH levels, we hypothesized that they could also affect COMT-catalyzed CE methylation. Although measurements of SAM and SAH were not initially collected, a secondary analysis of data from two nested case-control studies was performed to examine whether serum levels of folate, vitamin B12 (B12), pyridoxal 5'-phosphate (PLP), cysteine and homocysteine, in conjunction with COMT genotype, were associated with breast cancer risk. COMT(HH) (high activity COMT homozygote) breast cancer cases had statistically significantly lower levels of homocysteine (P = 0.05) and cysteine (P = 0.04) and higher levels of PLP (P = 0.02) than COMT(HH) controls. In contrast, COMT(LL) (low activity COMT homozygote) cases had higher levels of homocysteine than COMT(LL) controls (P = 0.05). No associations were seen between B12, COMT genotype, and breast cancer risk. An increasing number of COMT(L) alleles was significantly associated with increased breast cancer risk in women with below median levels of folate (P(trend) = 0.05) or above median levels of homocysteine (P(trend) = 0.02). These findings are consistent with a role for certain folate pathway micronutrients in mediating the association between COMT genotype and breast cancer risk.

Supportive role of a micronutrient appetite normaliser in convalescing patients

A total of 722 patients recruited from various clinics across Western India, particularly in Western Maharashtra and South Gujarat, recovering from a variety of clinical conditions such as infections of the respiratory tract, malaria, enteric fever, jaundice, surgical procedures and so on were administered a micronutrient appetite normaliser formulation (neogadine) for periods up to 30 days. There was a significant and steady increase in the scores of appetite and well-being during the study period. Very good to good response were reported in 83% of patients. Neogadine was well tolerated with no significant adverse effects on any patients. Based on past experience with this micronutrient formulation as well as the findings of the present study, it is reasonable to conclude that neogadine plays a useful supportive role in the restoration of appetite and well-being in conditions that apply to private practice situations in India.

[Nutrition and prostatic cancer]

Due to the major geographical variations affecting its clinical incidence, prostate cancer appears to be influenced by environmental factors, which may either promote or inhibit the development of this tumour. Diet appears to play a considerable role among these environmental factors. There are epidemiological and experimental arguments in favour of the role of diet in the development of prostatic cancer. Certain foods, such as fats, phenolic compound and other micronutrients such as vitamins or selenium have been reported to have an action on the natural history of prostate cancer. The authors present a review of the literature analysing the various potential actions of various foods.

Serum micronutrients and prostate cancer in Japanese Americans in Hawaii

Numerous dietary studies and several serum micronutrient studies have produced equivocal results on the relation of vitamins A and E to prostate cancer risk. To evaluate this association further, we conducted a nested case-control study in a cohort of 6860 Japanese-American men examined from 1971 to 1975. At the time of examination, a single blood specimen was obtained, and the serum was frozen. After a surveillance period of more than 20 years, 142 tissue-confirmed incident cases of prostate cancer were identified. Their stored sera and those of 142 matched controls were measured by high-performance liquid chromatography for the following: total carotenoids, lutein, zeaxanthin, beta-cryptoxanthin, lycopene, alpha-carotene, beta-carotene, total retinoids, retinol, total tocopherols, alpha-tocopherol, delta-tocopherol, and gamma-tocopherol. Odds ratios for prostate cancer, based on quartiles of serum micronutrient levels, were determined using conditional logistic regression analysis. The odds ratio for the highest quartiles were 1.8 (95% confidence interval, 0.9-3.9) for beta-cryptoxanthin, 1.6 (0.8-3.5) for beta-carotene, 0.8 (0.4-1.5) for retinol, and 0.7 (0.3-1.5) for gamma-tocopherol, but none of the differences was statistically significant. For the other micronutrients, the results were also unremarkable. The findings of this study indicate that none of the micronutrients is strongly associated with prostate cancer risk.