Pitfalls when accounting for supplement use in validation studies:

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1 Pitfalls when accounting for supplement use in validation studies: experiences from the European food consumption validation (EFCOVAL) study 15 June 2012, Sandra Crispim, Anouk Geelen, Lene Andersen, Jiri Ruprich, Inge Huybrechts, Lionel Lafay, Maureen Leeuw, Heinz Freisling, Nadia Slimani, Pieter van't Veer, Jeanne de Vries 8th ICDAM Rome, 2012

European Food COnsumption VALidation (EFCOVAL) Further development and validation of a European food consumption method to be used for estimation of the intake of foods, nutrients and potentially

2 European Food COnsumption VALidation (EFCOVAL) Further development and validation of a European food consumption method to be used for estimation of the intake of foods, nutrients and potentially hazardous chemicals within the European adult population Validation study in five European centers: Belgium, the Czech Republic, France, the Netherlands, and Norway Eur J Clin Nutr, Vol 65 Suppl 1, 2011 Br J Nut, Vol 105: Eur J Nut, in press Pub Health Nut, in press

3 EFCOVAL validation study 600 subjects (~120 per center) OBSERVED 2 x 24-h recalls (EPIC-Soft ) dietary intakes of protein, potassium REFERENCE (Recovery biomarker) 2 x 24-h urine collections for estimating urinary nitrogen (protein) and potassium Bias in protein and potassium intake (difference between intake and excretion) OBSERVED 2 x 24-h recalls (EPIC-Soft ) dietary intakes of fish, fruit and vegetable REFERENCE (Concentration biomarker) 1 x blood collection for estimating fatty acids in phospholipids and serum carotenoids Ranking of individuals according to their fish, fruit & vegetable intake (correlation between intake and concentration)

?? vs Aim: Report on the EFCOVAL experiences

4 How to account for supplement intake in these comparisons? Simply add supplements to the nutrient and food intake??? vs Aim: Report on the EFCOVAL experiences when accounting for supplement use in the validation of 24-h dietary recalls (24-HDR) in European centres.

Methods (1) Consumers of supplements containing protein, potassium, fatty acids and carotenoids were identified from: 1) 2x24-HDRs using EPIC-Soft software 2) a questionnaire on dietary supplement

5 Methods (1) Consumers of supplements containing protein, potassium, fatty acids and carotenoids were identified from: 1) 2x24-HDRs using EPIC-Soft software 2) a questionnaire on dietary supplement use, covering the past three months of intake To identify the nutrient content of the supplements, we searched: (1) companies websites (google search) (2) drugstores (3) national databases Certain and uncertain presence of nutrients in the supplement

7 Methods (2) For each centre, we compared the mean bias in protein and potassium intake with and without supplement use For fish and fruit & vegetable intakes, such straightforward assessment was not possible we compared the biomarker concentrations between groups of supplement users and non-users we also attempted to add an extra portion of the food group intake (fish, fruit and vegetable) in the consumption of supplement users but this approach became unrealistic

8 Results (1) % Supplement use of any kind in the EFCOVAL study 70% 60% 50% 40% 30% 59% Total Men Women 51% 20% 43% 10% 24% 19% 29% 0% Questionnaire (past 3 months) 2 x 24 HDR

9 Results (2) % subjects consuming supplements containing EPA+DHA, Carotenoids, Protein and Potassium in the EFCOVAL study 25% 20% 1% 15% 10% Uncertain Certain 5% 7% 2% 0% 0% 21% 5% 2% 4% EPA+DHA Carotenoids Protein (N) Potassium

10 Results (3) - supplements by type and country Supplements containing Protein (N) Supplements containing Potassium 12% 12% 12% 10% 8% 4% 0% 2.4% All countries 0% 1% 0% 0% NL BE NO CZ FR 8% 4% 0% 3.7% All countries 5% 2% 1% 1% NL BE NO CZ FR Supplements containing EPA+DHA Supplements containing Carotenoids 90% 12% 60% 63% 8% 9% 9% 5% 5% 30% 0% 21% All countries 11% 14% 9% 5% NL BE NO CZ FR 4% 0% All countries 2% 1% NL BE NO CZ FR

11 Results (4) Bias in protein intake with and without dietary supplement intake On average, men and women underreported protein intake by 8%. It varied from 2% (NO) to 13% (FR) On average, men underreported potassium intake by 7% and women by 4%. It varied from 17% underestimation (FR) to 6% overestimation (CZ) Comparison of bias in Protein and Potassium intake with and without the inclusion of supplement use were not statistically different across the European centres. For protein: 2-4% difference For potassium: 2-5% difference Within the countries that reported supplement intake

12 Results (5) Food group comparisons between intake and biomarker Pooled correlations: Usual fish intake vs EPA+DHA in phospholipids: 0.19 in men and 0.31 in women (p for heterogeneity >0.50) Usual fruit and vegetable intake and serum carotenoids 0.31 in men and 0.40 in women (p for heterogeneity >0.10) Biomarker levels (mean SE) of the total sample, users and non-users of specific supplements in the EFCOVAL validation study BE CZ FR NL NO % % 120 n % EPA+DHA n % EPA+DHA n EPA+DHA EPA+DHA n % EPA+DHA n All subjects Supplement users Non-supplement users Serum Serum Serum Serum Serum carotenoids [1] n n n n carotenoids carotenoids carotenoids carotenoids n All subjects Supplement users Non-supplement users [1] -carotene+ -cryptoxanthin+ -carotene+lutein+zeaxanthin.

Results (7) Unsuccessful attempt ID 1, Supplement user + vs 100 g of fish X g of fish to

unrealistic because it was not straight forward how to get an amount of the food group (e.g. fish) that could represent the supplement intake.

this variability was true or not, given the limited information from labels and small sample

13 Results (7) Unsuccessful attempt ID 1, Supplement user + vs 100 g of fish X g of fish to represent the supplement intake 7 % of EPA+DHA in total phospholipids This approach became unrealistic because it was not straight forward how to get an amount of the food group (e.g. fish) that could represent the supplement intake. The contents of nutrients varied greatly across countries and at the end we were not sure if this variability was true or not, given the limited information from labels and small sample sizes Bioavailability of supplements and food intake probably different

14 Discussion (1) The type of dietary supplement use in the five studied European centres seems to be different; The multitude of supplements available in the market makes the assessment of supplement use within and between countries challenging. How reliable was the information we collected to identify the presence of supplements?

15 Discussion (2) Overall, the validity assessment considering supplement intake in EFCOVAL was not straightforward and was hampered by a number of issues: difficulty to quantify the content of supplements; the user s ability to report detailed information about the supplements (e.g. brandname); the difficulty to consider the supplement intake in the validation of foods with concentration biomarkers (bioavailability issues and others)

16 Conclusion A degree of uncertainty remains in the evaluation of supplement use in the EFCOVAL study. Future evaluations should aim to collect precise data on the usual intake of dietary supplements and account for differences in their use between the countries.

17 Pitfalls when accounting for supplement use in validation studies: experiences from the European food consumption validation (EFCOVAL) study The EFCOVAL Study took place with the financial support of the European Community Sixth RTD Framework Programme (Contract FOOD-CT ).

Variation of bias in protein and potassium intake collected with 24-h recalls across European populations using multilevel analysis

Variation of bias in protein and potassium intake collected with 24-h recalls across European populations using multilevel analysis Sandra Crispim et al. presented by Anouk Geelen European Food COnsumption