Vegetarian diet

Appropriately planned vegetarian diets are healthful, nutritionally adequate, and provide health benefits in the prevention and treatment of certain diseases. It is especially important for vegetarians to avoid excessive amounts of junk food since a "refined food" vegetarian diet can be potentially dangerous with its extremely low nutrient levels. Also, be sure to consume enough calories. This can be a challenge for some vegetarians due to under-eating or excessive fiber in the diet. While fiber is beneficial, excessive amounts can interfere with mineral absorption. Good planning and forethought are essential. While it's true that several key nutrients found primarily in animal products cannot be obtained as easily from plant-based foods, there are ways to maximize your absorption and utilization of these important vitamins and minerals. To maintain optimum health, it is especially important that vegetarians consume adequate amounts of the following nutrients, either from foods, fortified foods or supplements.

Protein

Most people require about 0.8 grams of protein per kilogram of body weight, or 8 ounces of protein per day for a 160-pound adult. Vegetarians who do not eat dairy, eggs, legumes or processed soy products such as tofu or soymilk may need to eat 10–20% more protein than recommended in order to compensate for the lower digestibility of plant-based protein. Although it is commonly thought otherwise, protein-combining to obtain needed amino acids - such as eating beans with rice - is not necessary if a variety of plant foods is consumed over the course of a day.

Include a wide variety of protein-rich foods in the daily diet such as legumes, soy products such as tempeh, tofu, and soy-based meat substitutes, grains, nuts, seeds, dairy and eggs.  Legumes are an important source of lysine, the indispensable amino acid that is most likely to be deficient in a vegetarian diet. Include 2–3 servings of legumes (beans, peas and lentils) on a daily basis.

Iron

The Recommended Daily Allowance (RDA) of iron for vegetarians is 1.8 times higher than for non-vegetarians: 27mg. versus 15mg. This is because iron from plant foods is not as available to the body as iron from animal sources. Although iron intake and stores are usually adequate in vegetarians and vegans, young women and athletes should pay special attention to make sure their needs are met. In addition, lacto-ovo vegetarians who consume large quantities of dairy or eggs but few beans need to be aware that dairy is not a good source of iron and inhibits iron absorption. The iron in eggs also has poor bioavailability.

Ensure adequate intake of Iron

Ensure adequate intake eating a wide variety of iron-rich foods on a daily basis. Increase iron absorption by eating iron-rich foods along with foods high in vitamin C and other organic acids which can more than triple absorption rates. Decrease inhibitors of iron absorption in the diet, especially when consuming iron-rich foods. These include phytates found in wheat bran and soy, and tannins in tea, coffee and chocolate. The phytates in soy can be reduced by sprouting, fermenting (as in miso or tempeh) or soaking.

• Legumes, especially chickpeas, adzuki beans, lentils and kidney beans.

• Nuts and Seeds, most notably cashews, almonds, pumpkin seeds, sunflower seeds and tahini. Dried fruits

• Whole and enriched grains such as quinoa.

• Vegetables, particularly dark and leafy greens (parsley, watercress, dandelion, spinach, fennel, sorrel, nettles, etc.).

Zinc

Because the bioavailability of plant-based zinc is lower than from animal products, marginal deficiencies in zinc may be common in vegetarians. This is due to compounds called phytates, which are potent inhibitors of zinc absorption, especially when consumed in combination with calcium and zinc. In addition, plant foods tend to be lower in zinc concentrations than animal foods. Vegetarians may need up to 50% more zinc if their diet is high in phytates.

Ensure adequate intake of Zinc

• Eat a variety of zinc-rich foods every day including: legumes (adzuki, navy beans and split peas), nuts and seeds (pumpkin seeds, sunflower seeds and cashews), whole grains and wheat germ.

• Minimize inhibitors of zinc absorption by avoiding calcium supplements or eating calcium-rich foods in combination with foods high in zinc or high phytate foods. Use wheat germ instead of wheat bran, which contains significant quantities of phytates.

• Increase the bioavailability of zinc by soaking and sprouting grains, seeds, nuts and legumes, by leavening breads with yeast and sourdough, and by fermenting foods.

Iodine

Iodine is an essential mineral required for good thyroid function. Too little or too much iodine in the diet can lead to hypothyroidism, a precursor to disease. Vegetarians and vegans generally consume less iodine than the general population, but this varies depending on their intake of supplements, iodized salt, and seaweeds. Vegans who do not consume iodized salt may be at risk for iodine deficiency.Iodine absorption is inhibited by natural compounds in foods called goitrogens. Foods rich in goitrogens include soybeans and products made from soybeans, sweet potatoes, millet, flaxseed and cruciferous vegetables such as broccoli, cauliflower, kale and collards. Raw vegetables contain more goitrogens than cooked vegetables. However, consumption of these foods should not pose a problem for healthy people who ingest adequate amounts of iodine.

Ensure adequate intake of Iodine

• The Recommended Daily Allowance (RDA) for iodine is 150 mcg, which translates into 1/2 teaspoon of iodized salt or 1/10 teaspoon of kelp powder.

• The upper limit for iodine is 1100 mcg. Because seaweeds contain high amounts of iodine, be careful not to consume excessive amounts.

Essential Fatty Acids

Essential fatty acids are aptly named because they are truly essential to health. Since the body does not manufacture them, they must be obtained from the diet. Omega-3's are one class of essential fatty acids that include the fatty acids ALA (alpha-linolenic acid), EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). EPA and DHA in particular are important for maintaining cell membranes, including those of the brain and eyes, and for regulating bodily processes. However, vegetarian diets, particularly vegan diets, frequently do not supply adequate amounts of omega-3 essential fatty acids. On the other hand, plant-based vegetarian diets can deliver excessive amounts of omega-6 fatty acids, another class of essential fatty acids found in vegetable oils made from corn, soybeans and grape seeds, whole-grain breads and cereals. Omega-3's and omega-6's are both "good" fats but a high omega-6/omega-3 ratio promotes inflammation and other imbalances that can lead to disease. The ratio found in vegetarians is typically 10:1 to 20:1, whereas the recommended ratio is 2:1 to 4:1. For this reason, omega-6 fatty acid intake should be monitored.

Ensure adequate intake of essential fatty acids

• Increase your intake of omega-3 fatty acids by taking microalgae DHA supplements and including seaweed and omega-3 enriched eggs in the diet. Direct sources of EPA and DHA such as these are preferable because they are more physiologically active. Strive for 200–300 mg per day of EPA/DHA. Supplementation is an especially important consideration for pregnant and lactating women and people with diabetes or hypertension whose bodies cannot make EPA/DHA from its precursor, ALA.

• Eat foods or take supplements that are a source of alpha-linolenic acid (ALA), from which the body can manufacture EPA and DHA. These foods include flaxseed oil, hempseed oil, walnuts and canola oil. If your main source of omega-3 is from ALA, your requirements may be higher since conversion of ALA to EPA and DHA within the body is inefficient. If you are not consuming any of the direct sources of EPA and DHA mentioned above, aim for 4 grams per day of ALA.

• Avoid trans-fats present in hydrogenated or partially hydrogenated oils as well as excessive amounts of alcohol, both of which inhibit the enzymes that help produce EPA and DHA.

• Make monounsaturated fats, such as those found in olive oil, canola oil and high oleic safflower oil, the primary fats in the diet.

• Decrease your intake of vegetable oils containing omega-6 fatty acids such as corn, soy and grape seed oils. This includes products like salad dressings, mayonnaise, cookies and snack foods. Read the ingredient list on product labels to determine if omega-6 fatty acids are present.

Vitamin B12

It is challenging to maintain adequate levels of Vitamin B12 on a primarily plant-based diet. Because low levels of this vitamin increase disease risk and can negate the positive cardiovascular effects of a vegetarian diet, supplementation with vitamin B12 is strongly recommended. This is especially true of vegans who do not eat fortified foods, and for pregnant and lactating women for whom optimum vitamin B12 intake is crucial. The only reliable sources of B12 are animal foods, fortified foods or supplements. Seaweeds are not a reliable source since they typically contain analogs of the vitamin that are not physiologically active. Fermented foods, such as tempeh and miso, and organic vegetables are also poor sources of B12.

Ensure adequate intake of vitamin B12

• Eat B12 fortified foods, including fortified meat substitutes, cereals and non-dairy milk beverages, and nutritional yeast. Aim for at least 3 mcg of B12 in 2 or more meals. Absorption is best when small amounts of B12 are consumed at frequent intervals.

• Take vitamin B12 supplements at levels of 10 mcg per day. All people over the age of 50 should supplement with B12 because the body's ability to extract B12 from food sources declines with age.

• Lacto ovo vegetarians should include eggs and dairy in the diet.

Calcium

Calcium is essential for overall body health, helping to ensure proper muscle and nerve function as well as strong bones and teeth. Vegans are most likely to have calcium levels lower than the general population along with the lower bone density that implies. Inadequate dietary protein can also contribute to low bone density. Although dairy has long been touted as the best source of calcium, some low-oxylate greens such as broccoli, kale, collards, okra and Chinese greens actually deliver a more bioavailable calcium than milk can provide. Plant foods also have the added benefit of supplying vitamins and minerals that contribute to bone health, such as vitamins C and K, folate, magnesium, potassium, and boron. Calcium levels can be negatively affected by other dietary factors such as high sodium consumption, too much or too little protein, caffeine and soft drinks with phosphoric acid, so be sure to be aware of these, as well.

Ensure adequate intake of calcium

• Include sources of highly absorbable calcium in the diet such as the low-oxylate leafy greens mentioned above. Other sources include dairy products, tofu, soy beverages, sesame seeds, almonds, legumes, dried figs, and other calcium-fortified foods. Selecting a variety of calcium-rich foods throughout the day enhances absorption.

• Because they may interfere with calcium absorption, eat phytate-containing and oxalate-containing foods such as spinach, Swiss chard, beets and beet greens, and rhubarb at different times than calcium-rich foods.

Vitamin D

If you are a vegetarian with dark skin living in a northern clime, chances are you have less than optimal vitamin D levels. Sufficient vitamin D can be produced by exposure to the sun during warm months: 10-15 minutes on face and forearms for light-skinned people or 30 minutes to 3 hours for dark-skinned people. During cold months, you must depend on fortified foods or supplements.

Ensure adequate intake of vitamin D

• Warm-month sun exposure as detailed above.

• Consume vitamin D-rich foods, including fortified cow's milk, fortified soy beverages, fortified cereals, and egg yolks. Mushrooms, seaweed and some yeasts provide vitamin D, but not in enough quantity to meet daily needs.

• If supplementing, note that vitamin D3 (cholecalciferol) comes from animal sources - sheep's wool or animal hides - whereas vitamin D2 (ergocalciferol) is synthetic. Vitamin D2 is only 60% as bioavailable as D3, so requirements may be greater if D2 is the only dietary source.