Scurvy has long been associated amongst sailors as a predictable illness that developed after a month or two at sea due to insufficient amounts of Vitamin C. The predominant signs and symptoms of scurvy initially are associated with defective catecholamine (adrenaline and noradrenaline) synthesis followed by the changes associated with defective collagen synthesis. James Lind discovered these effects in 1753 when he observed behavioral changes in sailors who lost the initiative and will to work as well as the feeling of fatigue and apathy. The initial lassitude was then followed by changes to gums, hair follicles and poor wound healing.
It is unimaginable to consider Scurvy to be present in modern Australia however it has made a comeback. Professor Jenny Gunton, head the Diabetes Centre at the Westmead Institute for Medical research has discovered the presence of Scurvy in her patient that had an ulcer on her leg for 7 months that did not heal. Following were another 12 cases of Scurvy confirmed through bloods tests that were all treated with a simple course of Vitamin C. More alarmingly, Gunton established that the majority of these patients were consuming a fair amount of fruit and vegetables rich in Vitamin C, however they were simply overcooking them which destroys the Vitamin C content.
Humans cannot synthesis Vitamin C therefore it is essential to obtain adequate amounts in the diet. This recent discovery of scurvy highlights the need to discover the best cooking methods to obtain optimal levels of vitamins and nutrients in foods we consume. Recent studies have shown that there are several ways to enhance the availability of nutrients through proper selection of cooking method. One study found that steaming preserved the vitamin C content in a variety of vegetables whilst a loss was seen from pressure cooking (21%) and boiling (51%).
Recent reports investigate how popular cooking methods such as steaming, roasting, boiling, frying, sautéing, microwaving and pressure-cooking can impact the nutrient status and bioavailability of compounds in common vegetables. These reports also considered other factors such as domestic processing including washing, peeling, cutting, chopping and soaking. Reports found significant difference of nutrient status among cooking methods as they influence bile acid binding in vegetables. Bile acid binding lowers levels of cholesterol in the blood, helping to reduce the risk of heart disease. The following points summarize key findings in these studies:
• Steaming broccoli improved levels of total antioxidant capacity (TAC), glucosinolates, carotenoids, sulphorane and folate values. More specifically cooking time of 7.5 minutes maintained optimal nutritional quality.
• Steam cooking methods improved bile acid binding in beets, eggplant, asparagus, carrots, green beans and cauliflower when compared to the same vegetable uncooked.
• Sautéing was the cooking method with the most health potential for mustard green, kale, broccoli, cabbage and green bell pepper.
• Soaking and cooking peas and beans are effective in removing or reducing anti-nutrients such as tannins and phytic acid.
• The best cooking method for potatoes is sous-vide which is to cook in a vacuumed plastic pouch at precisely controlled temperatures. If that is too much for you then boiling was the second preferred method with 79% of the same retention of nutrients.
• Onions increased concentration of flavanols when sautéed by 7%, oven baked increased by 25%. This finding was only found in cooking for less than 5 minutes for 80% retention of flavanols.
• Interestingly boiling peas is the best method to retain folate, whilst pressure cooking decreases anti-nutrient starch.
• Cooking beans such as fava beans, lentils and chickpeas for more than 2 hours reduce folate by 50%.
• Absorption of iron can be improved by heat processing.
Being mindful of how we are cooking our foods can significantly improve our health and wellbeing. Reflect on your cooking methods at home and see how you can start making simple lifestyle changes to improve the health for you and your family. Share these simple cooking methods with your friends and family because the foods we eat are the foundation of good health and happiness.
Nutra Ingredients Asia 2016, Australias’ poor diets leading to unexpected cases of scurvy, <http://www.nutraingredients-asia.com>.
Bureau, S 2015, Are folates, carotenoids and vitamin C affected by cooking? Four domestic procedures are compared on a large diversity of frozen vegetables, Food Science and Technology, no.64, pp.735-741, <http://ac.els-cdn.com.ezproxy.endeavour.edu.au/S0023643815004430/1-s2.0-S0023643815004430-main.pdf?_tid=9a26a37e-bffc-11e6-abed-00000aacb35d&acdnat=1481500412_b03d24922907ac6829af100ec30d54f5>.
Fabbri et al 2016, Review Article, A review of the impact of preparation and cooking on the nutritional quality of vegetables and legumes, International Journal of Gastronomy and Food Science, <www/sciencedirectt.com>.
Blog by ATP Naturopath Racheal Lee