A food frequency questionnaire (FFQ) and carotenoid database with information on a-and bcarotene, lutein, lycopene and b-cryptoxanthin was prepared and used to compare the carotenoid intakes in five European countries: UK, Republic of Ireland, Spain, France and The Netherlands. Eighty, age-(25±45 years) and sex-matched volunteers were recruited in each of the five countries. A FFQ and carotenoid database was prepared of the most commonly consumed carotenoid rich foods in the participating countries and the information was used to calculate frequency and intake of carotenoid-rich foods. The median total carotenoid intake based on the sum of the five carotenoids, was significantly higher P , 0´05 in France (16´1 mg/day) and lower in Spain (9´5 mg/day,) than the other countries, where the average intake was approximately 14 mg/day. Comparison of dietary source of carotenoids showed that carrots were the major source of b-carotene in all countries except Spain where spinach was most important. Likewise, carrots were also the main source of a-carotene. Tomato or tomato products, were the major source of lycopene. Lutein was mainly obtained from peas in Republic of Ireland and the UK, however, spinach was found to be the major source in other countries. In all countries, bcryptoxanthin was primarily obtained from citrus fruit. Comparing the data with that from specific European country studies suggests that the FFQ and carotenoid database described in the present paper can be used for comparative dietary intake studies within Europe. The results show that within Europe there are differences in the specific intake of some carotenoids which are related to different foods consumed by people in different countries.Carotenoids: Food frequency questionnaire: Diet

Carotenoids form one of the most important classes of plant pigments and play a crucial role in defining the quality parameters of fruit and vegetables. Their role in the plant is to act as accessory pigments for light harvesting and in the prevention of photo‐oxidative damage, as well as acting as attractants for pollinators. Their function as antioxidants in the plant shows interesting parallels with their potential role as antioxidants in foods and humans. Carotenoids are products of the isoprenoid biosynthetic pathway. The enzymes leading to carotenoid biosynthesis have all been characterised, and more recently the genes encoding these enzymes have been cloned from bacteria, fungi and plants. New information on enzyme activities and the factors leading to the regulation of the pathway is reviewed. Vitamin A deficiency is a widespread problem in the developing world, causing blindness, particularly in the young. This has driven research into finding ways of introducing provitamin A carotenoids into staple crops, and this has recently been achieved in rice and canola through genetic manipulation. The fact that carotenoids show protective activity in vitro and in vivo against a variety of degenerative disease end points has also give impetus to studying whether increasing intakes of the commonly consumed carotenoids would have public health benefits in the developed world. Human intervention studies have been undertaken using supplements of β‐carotene rather than utilising foods with enhanced carotenoid levels, but no potential benefit has been shown. Indeed, there is evidence of an increased health risk from the consumption of β‐carotene supplements. These observations suggest that the threshold between the beneficial and adverse effects of some carotenoids is low and provides a strong stimulus to further understanding the functional effects of specific carotenoids. Specific needs for future research are identified in the review. © 2000 Society of Chemical Industry

Carotenoids are an excellent example of where poor understanding of food structure, complexity of behaviour during digestion, and inter-individual differences in response, lead to misinterpretation of study results. Four challenges associated with understanding and measuring carotenoid bioavailability are discussed: release of carotenoids from food structure and processing into an absorbable form (bioaccessibility), passage of carotenoids from gut lumen into the body (absorption), interpreting plasma response and inter-individual variation. Bioaccessibility of carotenoids is governed by characteristics of the food matrix, which affect the efficiency of physical, enzymic and chemical digestion. Carotenoids used as colorants are likely to be better absorbed because of the form in which they are dispersed in food. Extent of absorption of carotenoid supplements will depend on the proximity of dosing to the consumption of a fat-containing meal. Release of carotenoids from food plants occurs only when the plant cell is fractured and this occurs only during food preparation, processing and/or mastication, not during digestion. Following release from the food matrix, the major limiting factor is solubility of carotenoids in digesta. Absorption studies are best carried out by measuring chylomicron carotenoid excursion, with modelling of chylomicron turnover rate. In this way, inter-individual differences in lipoprotein metabolism can, in part, be taken into account before formulating conclusions on the rate and extent of absorption.