| Nutrition Notes from a Seminar by Brenda Davis |
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Brenda Davis is an amazing resource for nutritional information! I highly recommend that you get a copy of her internationally best selling book, Becoming Vegetarian, co-authored with Vesanto Melina and Victoria Harrison. Here are some excerpts from a recent seminar in Seattle at the EarthSave Taste of Health event. They apply to non-vegetarians as well. Click here to buy from Amazon
Zinc: Zinc deficiency can stunt growth, impair taste and appetite and compromise one's immune system. It can be tough to meet recommended intakes from natural sources and even tougher to absorb sufficient from the diet, so it is important to consume whole grains (refined grains have less than a third of the zinc provided by whole grains, legumes (including tofu and/or tempeh) and nuts and seeds in the diet. Soaking legumes, sprouting grains, roasting nuts and seeds and raising breads with yeast will increase zinc absorption. If you take a multivitamin/mineral supplement make sure it contains zinc (about 5 mg for children and 5-10 for adults), in addition to selenium and magnesium.
Calcium: Calcium is necessary for the maintainence of optimal bone health. However, calcium intake accounts for only about 11% of calcium balance. The most important factor in calcium balance is calcium excretion which is most adversely affected by protein and sodium. The more protein and sodium you consume, the more calcium you need. Thus people living in countries consuming a high protein, processed food diet (i.e. typical North American diet) require more calcium than those living in countries with a cereal-based food economy. Great plant sources of calcium include fortified soy milk, dark greens (broccoli, kale, collards, Chinese greens and other low-oxalate greens are best -- oxalates found in spinach, Swiss chard, rhubarb and beet greens bind with the calcium in these foods making it unavailable for absoption), raw almonds, sesame seed paste, legumes, figs and blackstrap molasses. Davis also mentioned that 50-70% of the calcium from most low oxalate vegetables is absorbable as compared to 32% in cow's milk.
Protein: She cites the World Health Organization's recommendation that 10-15% of your calories come from protein. In her book, Becoming Vegetarian, she gives specific recommendations for both vegetarians and non-vegetarians. When sufficinet calories are provided from nutritious plant foods, total protein intake is generally adequate.
Amino Acids: If protein intake is questionable, lysine is most commonly the limiting amino acid. If you focus on getting enough of this one, the others tend to take care of themselves. Including legumes (ie. beans, lentils, tofu) on a daily basis is the simplest way to do this. She states that soy provides an excellent balance of all essential amino acids and is the most versatile of all legumes.
Iron: Black tea and oriental green tea contain tannins, which when combined with iron form an insoluble compound. Try to avoid drinking at the same time as meals. Milk and cheese are low in iron and can decrease the iron availability from accompanying foods by up to 50%, thus it is important not to replace meat and poultry with cheese and other dairy products when switching to a vegetarian diet -- meat and poultry are best replaced by legumes. Cooking in a cast iron skillet can increase the iron content in foods by 2-16 times. Vitamin C increases iron absorption from other foods 2-3 times. Blackstrap molasses is a good source of iron, potassium, magnesium and vitamin B6. I use it to sweeten my Pero instant natural beverage, a caffeine free coffee substitute. I like Pero, but dislike the taste of coffee. Although spinach contains a lot of iron, it also contains oxalic acid which binds to the iron making it unavailable for absorption. Spinach is still a good source of other nutrients, however.
Oils: The three oils she uses are flax seed, canola and extra virgin olive. Davis recommends Omega Nutrition organic flax seed oil(or other organic, fresh pressed flax oil), but cautions that it spoils very quickly and must be kept in the refrigerator or freezer. One teaspoon a day is all most people need, although more may be beneficial for some people. I take 1 tablespoon to make sure that I finish the bottle before it spoils (you may wish to freeze half if you prefer to use less). Flax seeds are our best plant source of omega 3 fatty acids, which tend to be lacking in most diets (omnivores get much of their omega-3's from fish). Omega-3 fatty acids are precursors to hormone-like substances called eicosanoids which help regulate numerous body systems. They are necessary for the proper development of healthy cell membranes, including those of the brain and eye. Most people get insufficient omega-3's in their diet and are well advised to reduce their use of omega-6 rich oils (corn, sunflower, safflower, etc.) and increase their use of omega-3 rich oils such as flax and canola oil (flax is far more concentrated in omega-3's). Other good sources of omega-3 fatty acids include dark greens, tofu and other soy products, walnuts and wheat germ. Don't cook with flax seed oil, and take vitamin E with it to help counteract any free radicals reactions that may occur due to its unstable nature.
Vitamin D: Vitamin D: In addition to calcium and weight bearing exercise, vitamin D is also an important factor in bone health. Light skinned people need 10-15 minutes of warm sunshine to the hands and face per day to get their daily requirement of vitamin D, while dark skinned people need 1/2 hour or more. Both dark skin and sunscreens reduce vitamin D formation. Some foods are fortified with vitamin D and are particularly useful for insuring sufficient amounts during cold months where vitamin D production from sunshine may be limited or non-existent.
Riboflavin and B12: Riboflavin and B12: Vitamin B12 is found primarily in animal foods, so if you are consuming a plant-based diet, you need to have a reliable source of this nutrient. Seaweed, while often assumed to be an excellent source of vitamin B12, contains a mixture of vitamin B12 and B12 look-alikes (analogues that do not function like true B12 but attach to B12 receptors thereby potentially contributing to a B12 deficiency). Claims have been made that blue-green algae may be an exception, but further research may be needed to varify this. A great source of B12 and riboflavin is fortified nutritional yeast. This is not the kind of yeast you use to make bread (nutritional yeast does not leaven bread). She recommends Red Star T-6635+ vegetarian support formula (most other brands are not fortified with vitamin B12, thus are not sources of this nutrient -- read the label).
Wheat bran: Wheat bran is an excellent source of insoluble fibre making it a reasonable addition to the diets of those who consume low fibre, animal-centered diets. However, vegetarians who use plenty of wholegrains, legumes, vegetables and fruits generally get plenty of fibre, and daily use of wheat bran may reduce mineral absorption and/or make the diet too bulky for small children. Apparently, this does not apply to oat bran (which provides soluble fibre), and is still considered effective at reducing cholesterol (according to the latest clinical studies).