For most, the thought of eating raw or cooked food may not be a big deal. Sometimes we like our broccoli in a broccoli slaw salad (raw), and sometimes we enjoy eating it steamed (cooked).
After researching many of the popular “diets” available today, the Raw Food Diet was an interesting study and got me thinking about the potential advantages and disadvantages of consuming raw versus cooked foods. So, I thought we would investigate what some of the research has to say, let’s take a look…
Raw Food
Raw food can be defined as any uncooked, unprocessed, and often organic food (think apple picked from the tree, or cucumber fresh off the vine).
Each plant in its whole, raw state is composed of a complex blend of hundreds of chemical compounds. Many are nutrients like vitamins and minerals that we need daily for proper growth and maintenance of the human body. While other compounds (thousands of phytochemicals) found in these plant foods support the body in other ways, such as providing antioxidant properties that fight free radical damage to our cells.
So, what does the current research have to say about the nutritional value of eating food in its raw, whole form?
Garcia et al. found that long-term consumption of raw foods supports favorable concentrations of beta-carotene in plasma which lend to a normal vitamin A status for the individual.
Vitamin A (the name given to a group of fat-soluble retinoids) plays a role in our vision (without vitamin A we would not be able to see) immune function, reproduction, and cellular communication. Vitamin A plays a critical role in the development and maintenance of organs like the heart, lungs, and kidneys.
Animal proteins are the main source of vitamin B12 in the diet. Since animal meats are not typically consumed raw (exceptions may be foods such as oysters), vitamin B12 may be deficient in those that consume a strictly raw food diet.
Vitamin B12 plays a role in the synthesis of nucleic acids (think DNA, the building blocks of our genetic information!), red blood cells (that carry oxygen throughout the body), and it maintains myelin (essential to the proper functioning of our nervous system), among other functions.
Further, a deficiency in vitamin B12 can cause an increase in levels of homocysteine in the body. Elevated homocysteine levels are linked to higher risks for heart attacks and stroke as they can contribute to the formation of plaques that damage blood vessels.
Studies report that vegetarians have lower than average blood pressure, which is associated with less risk of cardiovascular diseases. A study by Chan et al. found that consuming raw vegetables over cooked more favorably supported blood pressure, although consumption of both raw and cooked vegetables supported a healthier blood pressure. The Chan study states that the lower blood pressure and raw food consumption may be due to the higher dietary fiber, protein, glutamic acid, vitamins like vitamin A, C, and E, and minerals such as calcium and magnesium.
When some raw foods, such as oats, are stored improperly, food safety becomes an issue as mold growth can encourage toxins, such as aflatoxins, to form. Excess temperatures can increase enzymes reactions which in turn decrease food quality, degrade nutrients in the food, and encourage the growth of microbes. The recommended temperature for storing oats is between 41 and 68 degrees Fahrenheit, to prevent mold growth.
The body’s ability to digest, absorb and use nutrients requires protein molecules called enzymes. Enzymes are destroyed when raw food, such as vegetables and fruits, are cooked or processed. When the temperature rises above 104 degrees Fahrenheit, enzymes (which are proteins remember ;)) begin to break down.
Consuming raw vegetables and fruits will help increase enzyme levels which lessen the body burden to create these protein molecules necessary to catalyze the all of the chemical reactions (e.g., in digestion and energy production) occurring in the body.
Cooked Food
Food preparation, such as cooking, can have both positive and negative effects on how well nutrients or phytochemicals are absorbed by the body.
Although Garcia et al. found raw food consumption to favorably affect the vitamin A status of an individual they also found that plasma lycopene levels were lower on a strict long-term raw food diet.
The bioavailability of protective compounds like carotenoids is enhanced when vegetables are cooked. For example, the lycopene (a fat-soluble phytochemical) found in tomatoes is absorbed at much higher rates when the tomatoes are cooked versus raw.
These carotenoids are important compounds as they act as antioxidants in the body and protect our cells from damage.
Lycopene has been shown to reduce blood pressure in those that were diagnosed as hypertensive (high blood pressure).
The Chan et al. study found that both raw and cooked vegetables favorably supported blood pressure, with raw coming out a bit ahead of cooked.
When vegetables are cooked, the chemical composition is altered which then impacts the effect these substances have on the individual who consumes them. For example, water-soluble nutrients like vitamin C and glucosinolates become less effective when boiled as their antioxidant properties are lost in the water.
Cooking some vegetables, however, can decrease certain food compounds that interfere with the digestive process. For example, cooking foods that contain oxalates (e.g., spinach, beets, chard, and parsley) will reduce the oxalate level and make them less likely to interfere with absorption of nutrients like calcium.
Other carotenoids, such as lutein and phytoene (found in broccoli) are enhanced when heated. Phytoene has been associated with reduced risk for prostate cancer, improved heart health and a reduction of inflammation in blood vessels.
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We can see with this short study that there are both advantages and disadvantages of consuming raw or cooked foods.
Perhaps the takeaway message here is that there will be gains and losses in consuming either raw or cooked whole foods, but both can be incorporated into a balanced diet that will support an individual's overall health and wellbeing. Both raw and cooked whole foods are an important part of a well-balanced eating plan for most healthy individuals.
Genesis 1:29 “And God said, "Behold, I have given you every plant yielding seed that is on the face of all the earth, and every tree with seed in its fruit. You shall have them for food.”
Genesis 9:3-4 “Every moving thing that lives shall be food for you. And as I gave you the green plants, I give you everything. But you shall not eat flesh with its life, that is, its blood.”
References:
Garcia, A. L., Koebnick, C., Dagnelie, P. C., Strassner, C., Elmadfa, I., Katz, N., . . . Hoffmann, I. (2008). Long-term strict raw food diet is associated with favourable plasma beta]-carotene and low plasma lycopene concentrations in germans. The British Journal of Nutrition, 99(6), 1293-300. doi:http://dx.doi.org/10.1017/S0007114507868486 Chan, Q., Stamler, J., Brown, I. J., Daviglus, M. L., Van Horn, L., Dyer, A. R., . . . Elliott, P. (2014). Relation of raw and cooked vegetable consumption to blood pressure: The INTERMAP study. Journal of Human Hypertension, 28(6), 353-9. doi:http://dx.doi.org/10.1038/jhh.2013.115 Pawlak, R., Lester, S. E., & Babatunde, T. (2014). The prevalence of cobalamin deficiency among vegetarians assessed by serum vitamin B12: A review of literature. European Journal of Clinical Nutrition, 68(5), 541-8. doi:http://dx.doi.org/10.1038/ejcn.2014.46 Obersby, D., Chappell, D. C., Dunnett, A., & Tsiami, A. A. (2013). Plasma total homocysteine status of vegetarians compared with omnivores: A systematic review and meta-analysis. The British Journal of Nutrition, 109(5), 785-94. doi:http://dx.doi.org/10.1017/S000711451200520X Sharma, S., & Rao, T. V. R. (2013). Nutritional quality characteristics of pumpkin fruit as revealed by its biochemical analysis. International Food Research Journal, 20(5), 2309-2316. Retrieved from https://search.proquest.com/docview/1491101445?accountid=158302 https://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/ http://www.ie.tsinghua.edu.cn/kbwang/Downloads/courseprojects/2010_AppStat/1.pdf http://www.bhia.org/lycopene.htm https://draxe.com/raw-food-diet/ http://healthyeating.sfgate.com/benefits-eating-raw-vegetables-4857.html https://www.globalhealingcenter.com/natural-health/benefits-of-raw-food-diet/ https://sciencing.com/effects-temperature-enzyme-activity-biology-6049.html Decker, E. A., Rose, D. J., & Stewart, D. (2014). Processing of oats and the impact of processing operations on nutrition and health benefits. The British Journal of Nutrition, 112, S58-64. doi:http://dx.doi.org/10.1017/S000711451400227X https://medlineplus.gov/druginfo/natural/554.html https://www.verywellfit.com/3-vegetables-made-healthier-when-cooked-4057179