Jeljer Hoekstra

Food and vessels: the importance of a healthy diet to prevent cardiovascular disease.

Aim We attempted to quantify the burden of cardiovascular disease that can be prevented by broader adherence to recommendations on dietary intake of key nutrients. Methods A computer model capturing the epidemiology of chronic disease and risk factors in the Dutch population was used to simulate differences in the occurrence of cardiovascular disease under various scenarios defined by levels of intake of saturated and trans fatty acids, fruit, vegetables and fish. The following scenarios were compared with the current situation: (i) the whole population adhering to recommendations (optimum scenario); (ii) a moderate improvement and (iii) increased intake of fruit as has been achieved in an actual intervention (‘fruit at work’). Other outcome measures assessed were (differences in) life expectancy and healthy life expectancy for a 40-year-old individual. Results In the optimum scenario, cumulative incidence prevented over a period of 20 years was 240 000 cases for acute myocardial infarction, or 30% of the expected number of cases, 328 000 (16%) for other coronary heart disease and 215 000 (21%) for stroke. For the moderate improvement scenario, the corresponding figures were 119 000 (14%), 163 000 (8%) and 105 000 (10%), respectively. The individual contributions of each of the separate dietary factors were greatest for fish, followed in decreasing order by fruit, vegetables, saturated and trans fatty acids. Only fish and fruit contributed to a decrease in strokes. In the optimum scenario, 1 year was added to the life expectancy of a 40-year-old individual and half a year in the moderate improvement scenario. Conclusion Broader adherence to recommendations for daily intake of fruit, vegetables, fish and fatty acid composition may take away as much as 20-30% of the burden of cardiovascular disease and result in approximately 1 extra life year for a 40-year-old individual. Promotion of a healthy diet should be given more emphasis in the prevention of cardiovascular disease.

Fish, contaminants and human health: Quantifying and weighing benefits and risks

This paper describes a quantitative risk-benefit assessment of fish consumption. We compare the net health effect expressed in DALYs of two scenarios. The reference scenario is the current fish intake of the Dutch population, which is less than what is recommended by the health authorities. The alternative scenario describes the health effects if the population consumes 200g of fish per week, which is close to the recommendation. All health effects due to fish consumption for which there is convincing evidence are incorporated in the assessment. The QALIBRA software (www.qalibra.eu) is used to simulate the two scenarios. The results show there is a net benefit for the population if it consumes 200g of fish each week.

Fish consumption during child bearing age: a quantitative risk-benefit analysis on neurodevelopment.

The fish ingredient N3-docosahexaenoic acid 22:6 n-3 (DHA) stimulates brain development. On the other hand methylmercury (MeHg) in fish disturbs the developing central nervous system. In this Context the IQ score in children is considered as an aggregate measure of in utero brain development. To determine the effect of DHA exposure on prenatal neurodevelopment the maternal DHA intake during pregnancy was compared with its epidemiologically observed effect on the IQ score of children. For MeHg the maternal intake was converted into its accumulation in the maternal body. The maternal body burden then was compared with its epidemiologically observed relationship with the IQ score. Taking the MeHg and DHA content of 33 fish species the net effect of these compounds on the IQ score was quantified. For most fish species the adverse effect of MeHg on the IQ score exceeded the beneficial effect of DHA. In the case of long-living predators a negative effect up to 10 points on the IQ score was found. The results of this study indicate that food interventions aiming at the beneficial effects of fish consumption should focus on fish species with a high DHA content, while avoiding fish species with a high MeHg content.

Potential effect of salt reduction in processed foods on health

BACKGROUND Excessive salt intake has been associated with hypertension and increased cardiovascular disease morbidity and mortality. Reducing salt intake is considered an important public health strategy in the Netherlands. OBJECTIVE The objective was to evaluate the health benefits of salt-reduction strategies related to processed foods for the Dutch population. DESIGN Three salt-reduction scenarios were developed: 1) substitution of high-salt foods with low-salt foods, 2) a reduction in the sodium content of processed foods, and 3) adherence to the recommended maximum salt intake of 6 g/d. Health outcomes were obtained in 2 steps: after salt intake was modeled into blood pressure levels, the Chronic Disease Model was used to translate modeled blood pressures into incidences of cardiovascular diseases, disability-adjusted life years (DALYs), and life expectancies. Health outcomes of the scenarios were compared with health outcomes obtained with current salt intake. RESULTS In total, 4.8% of acute myocardial infarction cases, 1.7% of congestive heart failure cases, and 5.8% of stroke cases might be prevented if salt intake meets the recommended maximum intake. The burden of disease might be reduced by 56,400 DALYs, and life expectancy might increase by 0.15 y for a 40-y-old individual. Substitution of foods with comparable low-salt alternatives would lead to slightly higher salt intake reductions and thus to more health gain. The estimates for sodium reduction in processed foods would be slightly lower. CONCLUSION Substantial health benefits might be achieved when added salt is removed from processed foods and when consumers choose more low-salt food alternatives.

A Tiered Approach for Risk-Benefit Assessment of Foods

Risk-benefit analyses are introduced as a new paradigm for old problems. However, in many cases it is not always necessary to perform a full comprehensive and expensive quantitative risk-benefit assessment to solve the problem, nor is it always possible, given the lack of required date. The choice to continue from a more qualitative to a full quantitative risk-benefit assessment can be made using a tiered approach. In this article, this tiered approach for risk-benefit assessment will be addressed using a decision tree. The tiered approach described uses the same four steps as the risk assessment paradigm: hazard and benefit identification, hazard and benefit characterization, exposure assessment, and risk-benefit characterization, albeit in a different order. For the purpose of this approach, the exposure assessment has been moved upward and the dose-response modeling (part of hazard and benefit characterization) is moved to a later stage. The decision tree includes several stop moments, depending on the situation where the gathered information is sufficient to answer the initial risk-benefit question. The approach has been tested for two food ingredients. The decision tree presented in this article is useful to assist on a case-by-case basis a risk-benefit assessor and policymaker in making informed choices when to stop or continue with a risk-benefit assessment.

Vitamins and minerals: issues associated with too low and too high population intakes

There is an ongoing increase in the availability of foods fortified with micronutrients and dietary supplements. This may result in differing intakes of micronutrients within the population and perhaps larger differences in intakes. Insight into population micronutrient intakes and evaluation of too low or too high intakes is required to see whether there are potential problems regarding inadequacy or excessive intakes. Too low population intakes are evaluated against an estimated average requirement; potential too high population intakes are evaluated against a tolerable upper intake level (UL). Additional health effects, seriousness, and incidence of these health effects are not considered but these can be taken into account in a benefit-risk assessment. Furthermore, authorities would like to regulate food fortification and supplementation in such a way that most of the population is not at risk of potentially high intakes. Several models are available for estimating maximum levels of micronutrients for food fortification and dietary supplements. Policy makers and risk managers need to decide how to divide the ‘free space’ between food fortification and/or dietary supplements, while protecting populations from adverse health effects.

Dietary patterns in relation to disease burden expressed in Disability-Adjusted Life Years

BACKGROUND Although diet is related to chronic disease risk and mortality, its association with total disease burden is not clear. OBJECTIVE We investigated the minimum impact of different dietary patterns on disability-adjusted life years (DALYs) by using individual longitudinal data. DESIGN A prospective cohort study was conducted in 33,066 healthy men and women aged 20-70 y recruited into the European Prospective Investigation into Cancer and Nutrition-Netherlands study during 1993-1997. We measured adherence to 3 a priori dietary patterns [the modified Mediterranean diet score (mMDS), the WHO-based Healthy Diet Indicator, and the Dutch Healthy Diet index] and 2 a posteriori dietary patterns. Two a posteriori methods were used to extract Western and prudent patterns. Participants were followed until the end of 2007 for the occurrence of and mortality from the most important chronic diseases. The disease burden was expressed in DALYs, which are the sum of Years Lost due to Disability and Years of Life Lost because of premature mortality. The associations between dietary patterns (per SD change in score) and DALYs were estimated by using a 2-part model and adjusted for relevant confounders (sex, age at recruitment, smoking status and intensity, educational level, marital status, job status, energy intake, and physical activity). RESULTS After an average follow-up of 12.4 y, higher adherence to the mMDS or prudent pattern was most strongly associated with healthy survival; per SD higher adherence to the mMDS or prudent pattern, fewer healthy life years were lost [51 d (-0.14 DALYs; 95% CI: -0.21, -0.08 DALYs) and 58 d (-0.16 DALYs; 95% CI: -0.23, -0.09 DALYs), respectively]. CONCLUSION In this Dutch study, of various dietary patterns evaluated, higher adherence to the mMDS or prudent dietary pattern was associated with a lower disease burden as assessed by DALYs.

Association between Lifestyle Factors and Quality-Adjusted Life Years in the EPIC-NL Cohort

The aim of our study was to relate four modifiable lifestyle factors (smoking status, body mass index, physical activity and diet) to health expectancy, using quality-adjusted life years (QALYs) in a prospective cohort study. Data of the prospective EPIC-NL study were used, including 33,066 healthy men and women aged 20–70 years at baseline (1993–7), followed until 31-12-2007 for occurrence of disease and death. Smoking status, body mass index, physical activity and adherence to a Mediterranean-style diet (excluding alcohol) were investigated separately and combined into a healthy lifestyle score, ranging from 0 to 4. QALYs were used as summary measure of healthy life expectancy, combining a persons life expectancy with a weight for quality of life when having a chronic disease. For lifestyle factors analyzed separately the number of years living longer in good health varied from 0.12 year to 0.84 year, after adjusting for covariates. A combination of the four lifestyle factors was positively associated with higher QALYs (P-trend <0.0001). A healthy lifestyle score of 4 compared to a score of 0 was associated with almost a 2 years longer life in good health (1.75 QALYs [95% CI 1.37, 2.14]).

Qalibra: a general model for food risk-benefit assessment that quantifies variability and uncertainty.

The EU project BRAFO proposed a framework for risk-benefit assessment of foods, or changes in diet, that present both potential risks and potential benefits to consumers (Hoekstra et al., 2012a). In higher tiers of the BRAFO framework, risks and benefits are integrated quantitatively to estimate net health impact measured in DALYs or QALYs (disability- or quality-adjusted life years). This paper describes a general model that was developed by a second EU project, Qalibra, to assist users in conducting these assessments. Its flexible design makes it applicable to a wide range of dietary questions involving different nutrients, contaminants and health effects. Account can be taken of variation between consumers in their diets and also other characteristics relevant to the estimation of risk and benefit, such as body weight, gender and age. Uncertainty in any input parameter may be quantified probabilistically, using probability distributions, or deterministically by repeating the assessment with alternative assumptions. Uncertainties that are not quantified should be evaluated qualitatively. Outputs produced by the model are illustrated using results from a simple assessment of fish consumption. More detailed case studies on oily fish and phytosterols are presented in companion papers. The model can be accessed as web-based software at www.qalibra.eu.

Dietary patterns in relation to quality-adjusted life years in the EPIC-NL cohort.

BACKGROUND Dietary patterns have been associated with the incidence or mortality of individual non-communicable diseases, but their association with disease burden has received little attention. OBJECTIVE The aim of our study was to relate dietary patterns to health expectancy using quality-adjusted life years (QALYs) as outcome parameter. METHODS Data from the EPIC-NL study were used, a prospective cohort study of 33,066 healthy men and women aged 20-70 years at recruitment. A lifestyle questionnaire and a validated food frequency questionnaire were administered at study entry (1993-1997). Five dietary patterns were studied: three a priori patterns (the modified Mediterranean Diet Score (mMDS), the WHO-based Healthy Diet Indicator (HDI) and the Dutch Healthy Diet index (DHD-index)) and two a posteriori data-based patterns. QALYs were used as a summary health measure for healthy life expectancy, combining a persons life expectancy with a weight reflecting loss of quality of life associated with having chronic diseases. RESULTS The mean QALYs of the participants were 74.9 (standard deviation 4.4). A higher mMDS and HDI were associated with a longer life in good health. Participants who had a high mMDS score (6-9) had 0.17 [95% CI, 0.05; 0.30] more QALYs than participants with a low score (0-3), equivalent to two months longer life in good health. Participants with a high HDI score also had more QALYs (0.15 [95% CI, 0.03; 0.27]) than participants with a low HDI score. CONCLUSION A Mediterranean-type diet and the Healthy Diet Indicator were associated with approximately 2months longer life in good health.