A review on factors influencing bioaccessibility and bioefficacy of carotenoids.

Vitamin A deficiency is one of the most prevalent deficiency disorders in the world. As shown by many studies plant food based approaches have a real potential on prevention of vitamin A deficiency in a sustainable way. Carotenoids are important as precursors of vitamin A as well as for prevention of cancers, coronary heart diseases, age-related macular degeneration, cataract etc. Bioaccessibility and bioefficacy of carotenoids are known to be influenced by numerous factors including dietary factors such as fat, fiber, dosage of carotenoid, location of carotenoid in the plant tissue, heat treatment, particle size of food, carotenoid species, interactions among carotenoids, isomeric form and molecular linkage and subject characteristics. Therefore even when carotenoids are found in high quantities in plant foods their utilization may be unsatisfactory because some factors are known to interfere as negative effectors.

A critical review on carotenoid research in Sri Lankan context and its outcomes.

As determined by countrywide assessments, vitamin A deficiency is a public health problem in Sri Lanka. Study of carotenoid profile and content could be important to nutritionists as some carotenoids act as precursors of vitamin A. Sri Lanka has a remarkable diversity of carotenoid sources. A number of Sri Lankan sources of carotenoids have been studied by many authors. This study reviews carotenoid research done in Sri Lanka, comparing results which are generally in conflict with a few relevant studies abroad, while focusing on problems of carotenoid research and concluding that it is difficult for a dietician to predict carotenoid intake due to marked biological variation. Therefore, any database on carotenoid covering the entire country has its limitations. Further that even if carotenoid profiles are known using exhaustive sampling, there can be no single method of calculating retinol equivalent (RE) and retinol activity equivalent (RAE) especially as carotenoid uptake and bioconversion could be multifactorially affected and subject to control mechanisms. Therefore, RE and RAE should be calculated differently for different types of plant materials may even be expanded so that a unique calculation depending on plant material and method of cooking.

A study of the serum carotenoids of eight cases of hypercarotenemia in Sri Lanka.

Over-consumption of absorbable carotenoids causes hypercarotenemia. Although hypercarotenemia is detected in Sri Lanka, a detailed study on this condition has not been carried out previously. Two millilitres of venous blood was drawn from hypercarotenemic patients (n=8) and examined by high-performance liquid chromatography for carotenoids and vitamin A. A common high-performance liquid chromatographic pattern in serum was shown by six of the cases with beta-carotene (9.9-35.7 microg/dl), beta-cryptoxanthin and monohydroxy metabolites collectively (5.3-48.5 microg/dl), and six to eight metabolites of dihydroxy, trihydroxy and polyhydroxy metabolites (22.5-282.1 microg/dl). Vitamin A levels were within the normal range (32-61 microg/dl). However, two cases identified were abnormal. The first of these showed low beta-carotene (3.5 microg/dl) and no beta-cryptoxanthin and monohydroxy metabolites, but normal dihydroxy, trihydroxy and polyhydroxy metabolites (128.2 microg/dl). However, the vitamin A level was high (75.2 microg/dl). The other case showed high beta-carotene (212.3 microg/dl) and beta-cryptoxanthin (49.3 microg/dl) but no normal monohydroxy, dihydroxy, trihydroxy and polyhydroxy metabolites. Instead there was an atypical metabolite (343.9 microg/dl). According to the present study, excessive intake of boiled, homogenized carrot and ripe papaw is the main causative factor for hypercarotenemia. Over-consumption of carotenoids-rich plant foods may be complicated in the case of individuals having defects of either the control of the 15,15'-dioxygenase activity or metabolism of carotenoids.

Insights of hypercarotenaemia: A brief review.

Carotenoids are generally 40-carbon tetraterpenoids responsible for most of the yellow, orange and red colours throughout the natural world. Pro-vitamin A carotenoids serve as the precursors of vitamin A. In addition to that, carotenoids exhibit range of important protective mechanisms in human health. Hypercarotenaemia is characterized by carotenodermia resulting in yellowing of the skin specially palms and soles. Hypercarotenaemia develops in subjects consuming high levels of carotenoid rich foods or ß-carotene supplements (>30 mg day-1) over a period of months. Less or normal intake of carotenoids very rarely gives rise to metabolic carotenaemia due to genetic defects of the enzyme 15-15'-carotenoid dioxygenase. Moreover, it is known that those with hypothyroidism and diabetes mellitus tend to develop hypercarotenaemia with the normal intake of carotenoid rich foods. Further, hypercarotenaemia has been reported in anorexia nervosa. However, recently some studies have been shown that there is no major correlation between carotenoid intake and hypercarotenaemia indicating that a genetic factor is at play in development of hypercarotenaemia. Therefore, the subjects appear to need to be genetically pre-disposed to hypercarotenaemia.

Content and in-vitro accessibility of pro-vitamin A carotenoids from Sri Lankan cooked non-leafy vegetables and their estimated contribution to vitamin A requirement.

Vitamin A deficiency is a public health problem in Sri Lanka, which affects especially pre-school children. Carrots (Daucus carota), pumpkins (Cucurbita maxima), squashes (Cucurbita moschata) and sweet potatoes (Ipomoea batatas) of orange, yellow-fleshed varieties are good sources of provitamin A carotenoids, but have not been studied in Sri Lanka in terms of the food as eaten. The content of carotenoids in each preparation method and the in-vitro accessibility of beta-carotene and alpha-carotene were determined by high-performance liquid chromatography. The in-vitro method simulates the conditions in the human intestinal tract. The mean contents in dry weight (DW) in different carrot preparations ranged from 406.7 to 456.3, from 183.7 to 213.5 and from 29.0 to 39.6 microg/g for beta-carotene, alpha-carotene and lutein, respectively. The content of carotenoids in different pumpkin preparations varied from 282.1 to 294.4 microg/g DW for beta-carotene, from 155.6 to 157.7 microg/g DW for alpha-carotene and from 218.0 to 228.2 microg/g DW for lutein. The squashes preparation had 44.6 and 40.0 microg/g DW for beta-carotene and alpha-carotene, respectively, and in sweet potatoes beta-carotene ranged from 204.3 to 210.3 microg/g DW. The results showed that the contribution to the recommended daily allowance is greater when these vegetables are prepared as a curry with coconut milk. The percentage contribution to recommended daily allowance from each vegetable cooked with coconut milk was 46.7, 21.8, 1.2 and 10.8 for carrots, pumpkins, squashes and sweet potatoes, respectively.