Bioavailability refers to the fraction of the nutrient that is stored or being available for physiological functions in the body (1).
Bioavailability of nutrients varies in the terms of the cooking process adopted, the type of ingredients used, temperature and the vessels used for cooking, individual health, and so on. Studies have also reported that various food combinations will have biochemical properties to enhance or reduce nutrient bioavailability, especially in the case of micronutrients like vitamins and minerals.
Here only the micronutrient bioavailability of plant-based diets is discussed.
Food combinations to enhance nutrient bioavailability
Green leafy vegetables with dal or fat or other vegetables or spices
Green leafy vegetables are a rich source of B- carotene (pro-vit. A), Iron, Zinc, and Vit. K. Cooking green leaves such as spinach or kale with fat, improves the bioavailability of B- carotene and Vit. K from them.
It was seen that when vegetables are exposed to the heat with the addition of turmeric, the bio accessibility of β-carotene was enhanced (2). Moreover, the addition of spices such as pepper and ginger acts as enhancers of β-carotene bioavailability (3). Most Indian recipes are similar to these.
Vitamin C helps in the absorption of iron from green leafy vegetables (4). Squeezing lime juice over a veg salad improves the absorption of iron from the salad. Cooking vegetables with vit. C rich other vegetables such as tomato, lemon, capsicum, and green chillies increase the bioavailability of iron and zinc in the food.
Minerals such as iron and zinc are absorbed and utilized better in the presence of sulphur-containing amino acids (5). Combining green leaves with dals, pulses, and garlic enhances the bioavailability of iron and zinc.
Green leafy vegetables such as parsley, spinach, drumstick leaves, and green cabbage, when cooked in the presence of fat, improve the bioavailability of vitamin K (6).
Onion or garlic with other vegetables or grains or pulses
Onion and garlic are known to be good sources of sulphur compounds. Onion or garlic when cooked with other vegetables, grains or pulses resulted in high bioavailable iron and zinc (7).
Fruits with milk
Combining fruits like mango and papaya with milk, deliver significantly higher amounts of bioavailable β-carotene. Making fruit shakes is a good choice (50 ml milk/10 g fresh pulp) (8).
Milk and its products
Lactose in milk is shown to improve the bioavailability of calcium (9). Hence, around 40% of calcium from dairy sources seems to be absorbed under normal conditions.
Combining yogurt with green leafy vegetables enhances calcium absorption. The acidic pH of yogurt ionized calcium and promoted intestinal calcium uptake (10).
Cooking paneer with green leaves such as palak, and fenugreek also improves iron and calcium bioavailability (11).
Fats with vegetables
Fats are essential for the absorption and utilization of fat-soluble vitamins such as A, D, E and K. Studies state that cooking carrots with fat enhances the bioavailability of β-carotene (12) than consuming raw carrots.
Cooking tomatoes with olive oil enhances the bioavailability of lycopene (antioxidant) (13).
Food combinations that inhibit nutrient bioavailability
Tea or coffee with a meal
Beverages containing polyphenols, like tea and coffee inhibit the absorption of (non-haem) iron from the meal. Studies concluded that drinking a cup of coffee or tea with a meal reduced iron absorption by 39% and 64% respectively (14).
Drinking coffee or tea one hour before or after a meal does not affect iron absorption.
Cooking vegetables with baking soda
Many recipes add baking soda in vegetables to retain the color/texture of the vegetable. But, a book on cooking food points out that “cooking vegetables with baking soda (sodium bicarbonate) can destroy nutrients such as vitamin C, vitamin D, riboflavin, thiamine, essential amino acids, etc (15).
Diet of people varies vastly. Non-communicable diseases (NCDs) due to micronutrient deficiencies are becoming one of the biggest concerns. Lack of nutritional knowledge and wrong food combinations are further aggravating the micronutrient deficiencies. Here the author is highlighting the good food combinations to enhance as well as combinations that inhibit the bioavailability of micronutrients.
Author: Dr. Shunmukha Priya. S (Research Supervisor, INFS)
- Cook, J. D., and Reddy, M. B. (2001). Effect of ascorbic acid intake on nonheme-iron absorption from a complete diet. The American journal of clinical nutrition, 73(1), 93–98. https://doi.org/10.1093/ajcn/73.1.93
- Gautam, S., Platel, K., and Srinivasan, K. (2010). Higher bioaccessibility of iron and zinc from food grains in the presence of garlic and onion. Journal of agricultural and food chemistry, 58(14), 8426–8429. https://doi.org/10.1021/jf100716t
- Halder, .M, Petsophonsakul, P., Akbulut, A.C., Pavlic, A., Bohan, F., Anderson, E., Maresz, K., Kramann, R., and Schurgers L., (2019). Vitamin K: Double Bonds beyond Coagulation Insights into Differences between Vitamin K1 and K2 in Health and Disease. Int J Mol Sci. 2019 Feb 19; 20(4)
- Gautam, S., Platel, K., and Srinivasan, K. (2010b). Higher bioaccessibility of iron and zinc from food grains in the presence of garlic and onion. J. Agric. Food Chem., 58: 8426–8429.
- Veda, S., Platel, K., and Srinivasan, K. (2007). Varietal differences in the bioaccessibility of βcarotene from mango (Mangifera indica) and papaya (Carica papaya) fruits. J. Agric. Food Chem., 55: 7931–7935.
- Miller, D. (1989). Calcium in the diet; food sources, recommended intakes, and nutritional bioavailability. Adv Food Nutr Res. 33:104–55. 10.1016/S1043-4526(08)60127-8
- Bronner, F., and Pansu, D. (1999). Nutritional aspects of calcium absorption. The J Nutr; 129: 9-12.
- Gupta,A., Gangwar, k., and Parihar, R (2016). In vitro bioavailability of calcium in products incorporated with green leafy vegetables., International Journal of Home Science; 2(1): 05-08.
- Hornero-Méndez, D., and Mínguez-Mosquera, M. I. (2007). Bioaccessibility of carotenes from carrots: Effect of cooking and addition of oil. Innovative Food Science & Emerging Technologies, 8(3), 407–412. doi:10.1016/j.ifset.2007.03.014
- Fielding, J. M., Rowley, K. G., Cooper, P., and O’ Dea, K. (2005). Increases in plasma lycopene concentration after consumption of tomatoes cooked with olive oil. Asia Pacific journal of clinical nutrition, 14(2), 131–136.
- Morck, T. A., Lynch, S. R., and Cook, J. D. (1983). Inhibition of food iron absorption by coffee. The American journal of clinical nutrition, 37(3), 416–420. https://doi.org/10.1093/ajcn/37.3.416
- Crosby, G. (2012) The Science of Good Cooking: Master 50 Simple Concepts to Enjoy a Lifetime of Success in the Kitchen (Cook’s Illustrated Cookbooks)., The Editors of America’s Test Kitchen and Guy Crosby., P. 504.