Common Nutritional Questions about Becoming Vegan
I am grateful to Brenda Davis who has worked with me to openly and accurately respond to common questions about shifting to a vegan diet.
A bit about Brenda: She is a registered dietitian, and she has been a featured speaker at international nutrition, medical and health conferences in over a dozen countries, and she has worked in different fields of nutrition.
Below, Brenda discusses why people go vegan and the benefits of making this shift. She also addresses some of the myths around vegan eating, and the things that we should keep an eye on.
Why do people choose to shift to a vegan diet and lifestyle?
People come to this diet and lifestyle for different reasons. Some make the shift because of serious health issues, others to protect themselves from, and prevent, such diseases. Others make the transition because they want to leave a softer carbon footprint on the planet. However, the most common reason for adopting a completely vegan diet is to reduce the pain, suffering and death of animals used for food.
Does eating a vegan diet provide any health advantages?
Yes, at least based on the research we have to date. Studies have demonstrated that people who eat plant-based diets have less obesity, heart disease, cancer and diabetes, than health conscious people who eat meat.
In comparison to health conscious omnivores, those eating vegetarian a vegan diet are about 28% less likely to develop heart disease, even accounting for, and controlling, variables such as body fat, exercise, smoking.
Those eating vegan diets are also 75% less likely to develop hypertension, 62% less likely to develop diabetes and 16-19% less likely to develop cancer, compared with health conscious omnivores.
Vegan diets have been shown to reduce risk, or provide, effective treatment for cataracts, diverticular disease, gallstones, kidney disease, and rheumatoid arthritis.
Are vegan diets really safe and adequate? What about during pregnancy and lactation, and for infants and children?
Yes. According to the Academy of Nutrition and Dietetics, well-planned vegan diets are appropriate for individuals during all stages of their life cycle, including pregnancy, lactation, infancy, childhood, and adolescence. This conclusion also applies to for athletes.
Of course, it is important that the diet is well-planned and that is why we take great care to provide appropriate guidelines for people at all stages of their life-cycle. You can read more in our most recent books - Becoming Vegan: Comprehensive Edition (2014) and Becoming Vegan: Express Edition (2013).
This is not new information. We have known this for quite some time. A large study in 1987 (775 vegan mothers in rural Tennessee) established that vegan diets do not affect birth weight, as long as vegans are health conscious, receive prenatal care, supplement their diets with the prenatal vitamins (B12, folate), and include reliable plant sources of protein, calcium, and iron. In fact the research scientists found that the vegan mothers had 0.1% risk of pre-eclampsia, compared with 5 to 10% in the general population.
In 1989 a study of 404 vegan children aged 4 months to 10 years showed that their height and weight was normal, although they were slightly slimmer than the general population. Again, the children had well planned diets that included plant protein, iron, calcium, and supplementary vitamin B12.
Can people get enough protein and all the essential amino acids without animal products?
Absolutely. All of the amino acids that we must get are made by plants. Most vegans consume 10-15% of calories from protein and this is exactly what is recommended by WHO. People who do not eat enough calories may not get enough protein, and people who eat mostly fat and sugar (e.g. chips and soda) may fall short as well. Finally, those eating very high fruit diets could also come up short.
Aren't vegans at greater risk for iron deficiency anemia?
Iron deficiency is the primary nutritional deficiency worldwide, and in north America, for people on any diet, especially for women of childbearing age, infants, and teens. However there is no more iron deficiency anemia in vegans than in the general population.
In the past, nutrition texts rated the non-heme iron from plant foods as being inferior to the heme iron in meat, since generally a lower percentage of non-heme is absorbed. We’re now aware that non-heme iron may provide an advantage, keeping us on safe ground between too little and too much iron.
Plant sources of iron are ideal, as the body has some control over absorption efficiency and can adjust uptake to suit needs. If our iron reserves are low, we absorb more iron from plant foods; if abundant, our intestines block the absorption of this non-heme iron. Pregnant women can absorb over 60% more iron than they did before pregnancy.
Do vegans need to worry about vitamin B12?
YES! Vitamin B12 is the nutrient that is generally of greatest concern in vegan diets. Reliable sources for people under 50 years are animal products (people over 50 may not be able to remove the B12 from the protein that it is bound to in animal sources).
Others (vegans and those over 50 years) are well advised to rely on fortified foods or supplements for their B12.
Insufficient B12 causes anemia and nerve damage. It can also cause homocysteine to rise, increasing risk of atherosclerosis. Vegans can easily solve the B12 problem by taking a B12 supplement twice a week.
Can a person get enough calcium if they eliminate dairy products?
Absolutely. Before humans domesticated animals, their calcium intakes were estimated to be 1,000-2,000 mg per day. All this without a single drop of mammal milk. Most of this calcium came from calcium-rich leafy greens. Availability of the calcium in greens differs considerably. Calcium is very well absorbed from high calcium, low-oxalate green veggies such as bok choy, kale, napa cabbage, broccoli, watercress, and mustard and turnip greens. Collard and dandelion greens are fair calcium sources (they are higher in oxalates). Calcium is very poorly absorbed from very high oxalate greens such as spinach, beet greens and Swiss chard. Calcium is also present in oranges, calcium-fortified juices, almonds, sesame tahini, and blackstrap molasses.
It’s added to fortified non-dairy milks and to tofu, which makes them excellent sources of calcium. Using these foods makes it easier to meet the recommended targets for calcium.
Aren't vegan diets too high in carbohydrates?
In obesity-ridden developed countries, popular low-carb diets urge people to shun carbohydrates in favor of meat-centered, protein-rich fare, claiming that carbs are responsible for weight gain and numerous diseases. The only foods that are free of carbohydrates are meat, fish, poultry, and oil. Plants are our primary dietary sources of carbohydrates.
The typical benefits people experience when they adopt low carb diets are related to omission of sugar, refined starchy foods, plus the processed fat that often comes with them, e.g. in baked goodies, fried chips, candy and soda pop.
The benefits do not come from omitting lentils, green peas, chickpeas, broccoli, asparagus, cucumber. Yet in all of these and other whole plant foods (with the exception of nuts and seeds) about 58-92% of the calories come from carbohydrates.
We must remember that the healthiest, longest living people in the world, consume plant-centered diets that are relatively high in carbohydrates (50-80% of calories).
When carbohydrates come from unrefined or whole food sources, they are consistently beneficial. It is only when they are refined or stripped of their protective components that they are damaging to health. We need at least 130g of carbohydrates for brain function per day. You get about 30g of carbohydrates in a cup of lentil or split pea soup.
Don't we need to eat fish to insure sufficient omega-3 fatty acids in the diet?
No. Most adults can get sufficient omega-3’s from:
- 2 teaspoons of ground flaxseeds or chia seeds
- ¼ c hempseeds
- ⅓ c walnuts
- 1½ t flaxseed oil
- 1½ T hempseed oil
- 2½ T canola oil
For those who need a direct source of long-chain omega-3 fatty acids, a supplement of 200-300 mg vegan DHA/EPA 2-3 x/ week may be beneficial.
Do vegans need to take nutritional supplements?
Not if sufficient B12-fortified foods, iodine-rich foods and a source of vitamin D (e.g. sufficient sunlight) are consumed. Otherwise, vegans are advised to take:
• Vitamin B12 :25-100 mcg daily or 1,000 mcg 2x/wk or 3 x/day B12 fortified foods
• Vitamin D (if insufficient exposure to warm sunshine): 15 mcg (600 IU) to age 70; 20 mcg (800 IU) after 70. {5 to 50 mcg (1,000-2,000 IU) is safe}
• Iodine: 150 mcg
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