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Saturday night I was fortunate to hear Vesanto Melina discuss some very important issues about raw food vegan diets. Besides Becoming Raw, Ms. Melina has co-authored Raw Food Revolution Diet, Becoming Vegan, Raising Vegetarian Children, Food Allergy Survival Guide and The New Becoming Vegetarian. She has taught nutrition at the University of British Columbia and at Seattle's Bastyr University. In short, she's spent most of her life studying and writing about plant-based nutrition so she is truly an expert in this field.
In her talk, she discussed 4 controversial questions about raw food diets:
(1) What contributions do plant enzymes make to digestion?
(2) Are cooked foods toxic?
(3) Can we get enough vitamin B12 from plant foods or from the production of B12 in your intestines?
(4) Can raw food diets reverse chronic disease?
|Vesanto Melina (right) lecturing at a vegan potluck in Santa Rosa, California|
Most raw foodists regard the preservation of enzymes as the holy grail. It is believed that the enzymes found in uncooked food can work together with the enzymes produced by the body itself to more efficiently digest food. This may reduce the amount of enzymes the body has to produce allowing it to preserve its energy for other activities. Raw foodists often experience high energy which many attribute to the consumption of raw food enzymes. I myself have experienced high levels of energy when on a raw food cleanse (when I go completely raw for 1 month) followed by extreme fatigue when I consume my first cooked meal after my cleanse.
Contrary to these beliefs, Ms. Melina says that enzymes are not the core reason for the benefits of a raw food diet. She claims the science shows that food enzymes can provide some initial digestion which can begin when food is chopped, juiced, pureed and chewed, but the amount of enzymes in food is much smaller than those produced by the body. Because of their relative quantities, some experts feel that plant enzymes do not play a significant role in human digestion. However, she gave two important examples where plant enzymes are critical in providing health benefits and therefore the foods should be not be cooked to obtain maximum benefits. These are myrosinase and alliinase.
Myrosinase is an enzyme found in raw cruciferous vegetables iike broccoli, kale, cauliflower, bok choy, brussels sprouts, etc. These veggies all contain important sulfur-containing compounds called glucosinolates. Myrosinase allows the conversion of glucosinolates to isothiocyanates which are bioactive metabolites known to trigger other enzymes in the body to prevent and fight cancer. But unfortunately myrosinase is deactivated at 140 degrees F. Bottom line, if you cook cruciferous veggies more than lightly steaming them, you may lose much of their cancer fighting abilities!
Allinase is an enzyme found in raw garlic and onions and other vegetables in the allium family. Other vegetables in the allium family include chives, green onions and leeks. Allinase converts an organosulfur compound found in allium vegetables to allicin which has many powerful properties. Allicin is known to have anticancer, antibacterial, antifungal, antimicrobial and antiparasitic properties. It also is known to help lower cholesterol, thin blood and reduce inflammation associated with arthritis. Unfortunately, allinase is destroyed by heat. If you let garlic sit for 10 to 15 minutes after crushing or mincing it before it is cooked, it allows sufficient conversion to allicin and it can withstand some amount of cooking. However, depending on the heat and amount of cooking time, much of the health properties of the garlic may still be lost.
Are Cooked Foods Toxic?
Ms. Melina believes, as I do, that there is no need to eat a 100% raw diet. See my post on Raw Food Diet - How raw do you need to be? Many foods can be boiled and steamed and still provide important nutrients. However, she discussed some of the harmful effects that cooking can have:
I remember seeing the first infrared burner on BBQ grills thinking that they should just call it the "cancer feature". These burners can grill meat over 700 degrees F!
Ms. Melina discussed the health damaging by-products that can be formed when foods are subjected to very high temperatures. HCAs (heterocyclic amines) are generated when animal products like meat, poultry, fish and eggs, are barbecued, grilled or fried. Consumption of HCAs can increase the risk of colorectal, stomach, pancreatic and breast cancers. Grilling veggies does not produce HCAs.
PAHs (polycyclic aromatic hydrocarbons) are generated from grilled or charred meat, poultry, fish, grains, sweets and fats. An example of this is burnt toast. Like HCAs, PAHs can damage DNA and PAHs have been linked to cancer. AGEs (advanced glycation end products) are formed when proteins are cooked with sugars without water. Browning is an indication of AGEs, such as browned meats, bread crust, cookies, etc. These have been linked to accelerated aging, impaired immune systems, heart, nerve, eye and kidney diseases as well as diabetes. Acrylamines form when foods high in carbohydrates and low in protein are subjected to high cooking temperatures exceeding 248 degrees F. This is extremely bad news for all of you potato chip and french fry lovers! Consumption of acrylamines may also be carcinogenic.
Vitamin and Mineral Loss
Besides forming carcinogenic by-products, Ms. Melina pointed out that as much as 50% to 80% of vitamins can be lost in the cooking process and 30% to 40% of minerals can end up in the cooking water (so use it to make soup!). By eating foods raw, you will get the optimal amount of vitamins and minerals.
Phytochemicals, or plant chemicals, are what gives plants their colors and many other characteristics. When consumed, they have numerous health benefits, many of which are lessened by the cooking process. But this is not always the case. Some phytochemicals increase with cooking. For example, studies show that the availability of the phytochemical, lycopene, increases when tomatoes are cooked. It is believed that cooking breaks down the cell wall. A list of vegetables and what effect cooking has on their phytochemicals can be found on pages 49-50 in Ms. Melina's book, Becoming Raw.
Like many other well regarded nutritionists, Ms. Melina also agrees that you cannot possibly get enough vitamin B12 from plant food or from the production of B12 in your intestines. Vegetables purchased today do not contain B12 producing bacteria (as they are free of dirt) and the B12 produced in your body is done further down the intestine beyond the point the body is able to absorb and utilize it. Raw food vegans must supplement as they do not eat fortified foods. Vegetarian formulated Red Star nutritional yeast is also a good source of vitamin B12 but she still highly recommends supplementation. By the way, if you're not supplementing and haven't gotten into trouble yet, it's because your body is extremely good at recycling vitamin B12. But eventually it will catch up with you and deficiency can cause some life threatening health issues like megaloblastic anemia and severe nervous system problems. Fatigue, depression, confusion and irritability are symptoms of B12 deficiency.
Ms. Melina also recommended supplementing with vitamin D (her own vitamin D levels were woefully low despite her visit to sunny Hawaii) and perhaps DHA omega 3.
Can Raw Food Diets Reverse Chronic Disease?
There is scientific evidence that raw food diets can reverse some chronic diseases. Specifically, they have been shown to offer significant benefits for those suffering with rheumatoid arthritis, fibromyalgia and those who are overweight or obese. There is suggestive evidence that a raw food diet may also provide protection against cancer and should be a good supplemental treatment to those who already have cancer. It is also widely acknowledged that raw food diets have the potential to prevent and reverse cardiovascular disease due to the high content of antioxidants and phytochemicals. The caveat here is that without B12 supplementation, there is an increase in homocysteine and therefore an increased risk of heart disease! Supplementation with vitamin D and omega 3 fatty acids is also required. And finally, there is also strong suggestive evidence that raw food diets can prevent and reverse type 2 diabetes. (See my post where my friend Kannan prevented type 2 diabetes and metabolic syndrome with a raw food diet). Ms. Melina also indicated that there were instances of people with type 1 diabetes who responded favorable to a raw food diet. The above vitamin and fatty acid supplementation is also recommended to achieve the benefits of protecting and reversing all the mentioned disorders.
To summarize, Ms. Melina thinks that "Raw Rocks" as she states in her book. There are many advantages to raw plant consumption as it can help us obtain and maintain a healthful body weight and protect us from many diseases. Raw plants contain high amounts of compounds that are good for us and fewer compounds that make us sick. This contributes to the ability of this food regimen to reverse some chronic illnesses.
However, she does not feel that the majority of benefits from a raw food diet come from living enzymes and their ability to significantly contribute to digestion. She also points out that several critical nutrients can not be derived solely from raw plant sources, especially vitamin B12. And, Ms. Melina feels that there is an important place for cooked plant foods in our diet and does not think that people need to be 100% raw.
A big thanks to Vesanto Melina for a wonderful lecture and discussion on this very important topic!