A lot of people are very concerned about protein.  Tell someone you're vegetarian, and the first objection you'll likely get is "But where do you get your protein?" (Nevermind what kind of shape the person asking is often in.)  I personally have not let the protein issue concern me, choosing instead to cook and eat a wide variety of foods and trust that I'll get enough protein and all of the essential amino acids, and I've never felt better.

The one protein supplement I use is hemp protein, which has a moderate amount of protein and which I believe to be healthier than either whey or soy.  If you want to try it, you can get hemp protein at iHerb.com and use the code RAZ652 at checkout to get $5 off your first order.

For someone who cooks all the time, eating a variety of whole foods is an easy solution.  But for someone whose schedule doesn't allow for much cooking at home, getting enough protein (and the right kinds) can be a problem.  My mother is one such case.  A few weeks after she went vegetarian, she noticed that something wasn't right; she didn't have the energy that she did when she ate meat.  Suspecting that the problem was not enough protein, she spent a few weeks researching amino acids and vegetarian protein sources.

This page is the result of such research.  If you're in a similar situation, I hope it helps you out.

A little background

There are 20 amino acids that link together to form peptides.  Peptides are then linked together to form proteins.  There are thousands of different proteins that carry out a large number of jobs in our bodies.  We don’t have to worry about consuming all the proteins- our body makes those.  We just need to make sure we have all 20 basic “building blocks” (amino acids).  Our body (except with certain illnesses or genetic abnormalities) makes 11 of them from chemicals already present in our body, so we really only need to be concerned about consuming the nine that our body cannot make.  The nine amino acids that we need to get from our diet are called “essential amino acids.”

Chemical makeup and the role of amino acids in the body

The molecule of an amino acid is made up of a carboxyl group of atoms (one carbon, two oxygen and one hydrogen), an amine group (one nitrogen and two hydrogen atoms) and a side chain.  The side chains consist of a combination of carbon, hydrogen, sulfur, nitrogen and/or oxygen and it’s the configuration of these that differentiates one amino acid from another.  The branched-chain amino acids are isoleucine, leucine and valine and these are the amino acids responsible for muscle structure.

The amino acids tyrosine, phenylalanine and tryptophan are the aromatic amino acids, having a side chain with a ring-shaped formation and are necessary for the production of the neurotransmitters serotonin and melatonin.  Serotonin is important for healthy and restful sleep as well as elevating and stabilizing mood and in the modulation of human sexuality, appetite, and metabolism.  Melatonin is important in the regulation of the circadian rhythms (the interior body clock) and is a powerful antioxidant associated with the protection of nuclear and mitochondrial DNA.

Lysine plays an important role in absorbing and conserving calcium and in the formation of collagen.  Too little lysine in the diet can lead to kidney stones and other health related problems including fatigue, nausea, dizziness, loss of appetite, agitation, bloodshot eyes, slow growth, anemia, and reproductive disorders. At risk for a low lysine disorder could be vegetarians who follow a macrobiotic diet and athletes involved in frequent vigorous exercise.

Daily requirements and good non-meat sources of specific amino acids

The requirement for the non-essential amino acids has changed considerably over the last 20 years.  The following table lists the recommended daily amounts for adults by the World Health Organization, along with the standard one-letter abbreviation.  (Recommended daily intakes for children during their first year can be as much as 150% higher, and 10-20% higher for children three years and older.)

Important: This chart lists the vegetable/nut/legume sources (plus fish sources, for you pescetarians) with the highest amounts of the amino acids per a 200 calorie serving.  However, this may NOT be the most practical source!  For instance, 200 calories of watercress provide an abundance of essential amino acid daily requirements, but having only 4 calories per cup, 200 calories would equate to 50 cups!  Or egg whites are a terrific source of essential amino acids, but 200 calories of egg whites mean you would need to eat 11 eggs!  Not my way of starting the day.  With that in mind, I’ve compiled a list of great, enjoyable food sources to meet the daily requirements, at the end of this page.

*Some sources claim histidine to also be an essential amino acid as it is additionally required by infants and growing children. Also, cysteine can usually be synthesized by the human body under normal physiological conditions if a sufficient quantity of methionine is available.

Concerns over soy supplements as the main source of amino acids

If you choose to supplement your diet with whey or soy protein, consider the following:  There is a mixed consensus about whether soy contains all of the essential proteins.  Some sources claim that it does.  Others site that it is not complete- missing methionine, while others report that soybeans are “limiting” in methionine and cysteine.

Methionine assists in breaking down fats and thus prevents build-up of fat in the arteries and liver.  Since it is converted to cysteine, it also assists with the removal of heavy metals (including lead) from the body.  It’s also a powerful antioxidant, removing free radicals produced in the natural metabolic processes of the body.

But limiting or lacking in even one amino acid can have serious health implications.  Muscle and other protein structures could be dismantled to obtain the one amino acid that is missing.  Many experts suggest combining soy products with legumes or whole grains to achieve the ideal balance for the body’s requirements.  Or, if relying heavily on soy for protein requirements, it would be good to consume foods high in methionine, such as sesame seeds and brazil nuts.  Except for spinach, potatoes, or corn, most fruits and vegetables contain little methionine.

Cysteine can usually be made by the human body if a sufficient quantity of methionine is available.  Otherwise, cysteine can be found in eggs, milk, whey protein, ricotta, cottage cheese, yogurt, red peppers, garlic, onions, broccoli, brussels sprouts, oats, granola, wheat germ

An interesting note:  A heavy dose of cysteine may be useful in preventing or combating some of the negative effects of alcohol, including liver damage and hangover.

Concerns over soy-rich diets

The jury is definitely out as to whether consuming a soy-rich diet is good for you .  Many reports indicate that soy's abundant isoflavones can prevent illness and promote good health.  Isofavones are a type of phytoestrogen, a plant hormone that in chemical structure resembles a weak form of human estrogen.   The isofavones can compete at estrogen receptor sites, blocking the stronger version produced by the body.   Proponents claim that this can reduce the risk of breast and prostate cancer, reduce the risk of heart disease, reduce menopausal symptoms and can slow or reverse osteoporosis.

Other studies present a strong case supporting the dangers of excess soy consumption, claiming that soy products contain:

• Phytoestrogens: (isoflavones) genistein and daidzein, which mimic and sometimes block the hormone estrogen (not a positive result as in the studies above)
• Phytates: block the body's uptake of minerals
• Enzyme Inhibitors: hinder protein digestion
• Hemagglutinin:  a clot-promoting substance which causes red blood cells to clump together. These clustered blood cells cannot properly absorb oxygen for distribution to the body's tissues, and are unable to help in maintaining good cardiac health.

With so much conflicting information, I would be hesitant to rely heavily on soy products  or soy-related supplements to satisfy the bulk of my protein requirements.

Best Protein Sources for Vegetarians

I’ve compiled a list of some of the best protein sources within different food groups, comparing what could be considered a normal serving:

Food                                           Amount          Calories    Protein      Notes

Nuts and Seeds

Pumpkin/squash seeds       1 oz, 85 seeds    126 cal        5 gm             all aa in proper ratio

Black walnuts                           1 oz                       173 cal        7 gm            low in lysine

Pine nuts                     1 oz, 167 kernels         190 cal      4 gm         low in lysine

Roasted almonds         1 oz, 22 count             171 cal       6gm         low in lysine and methionine

Pistachios                     1 oz 49 count              161 cal        6gm          all aa in proper ratio

Sunflower seeds                     1 oz                  166 cal         5 gm         low in lysine

Peanuts without shells           1 oz                   160 cal         7 gm         low in lysine

Cashews                         1 oz 18 kernels         164 cal          4 gm        all aa in proper ratio

Hemp seeds                            2 T                   160 cal         11gm         all aa in proper ratio

Flax seeds                               1 T                    100 cal         4 gm

Dairy Products

Ricotta cheese lowfat                ½ c          171 cal              14 gm        all aa  high in lysine

Romano cheese                       1 oz           108 cal               9 gm         all aa in proper ratio

Cheddar cheese                       1 oz           113 cal               7 gm         all aa in proper ratio

Provolone cheese                    1 oz             98 cal                7 gm        all aa  high in lysine

Mozzarella                              1 oz              71 cal               7 gm        all aa high in lysine

Parmesan                                 1 oz            116 cal                7 gm       all aa high in lysine

Gouda cheese                           1 oz           100 cal                 8 gm       all aa high in lysine

Swiss cheese                            1 oz            100 cal                8gm        all aa high in lysine

Feta cheese                      ½ c crumbled      200 cal              21 gm       all aa

Cottage cheese 2% low fat      1 cup          163 cal               28 gm       all aa

Egg                                       1 whole           77 cal               6 gm         all aa

Egg whites                           1 whole           16 cal                4 gm         all aa

Milk                                      1 cup              137 cal             10 gm        all aa

Yogurt low fat                      1 cup               137 cal            14 gm        low in tryptophan

Vegetables

Corn yellow canned             2/3 cup               80 cal              3 gm        high in lysine

Sun-dried tomatoes          ½ cup (1 oz)           72 cal             4 gm         lacks 5 aa

Soy beans                             1 oz                      35 cal            4 gm        all aa, but a little low in methionine+cystine, phenylalanine+tyrosine

Peas                                     2 oz                        70 cal              4 gm     low in tryptophan

Cowpeas (blackeyes)          2 oz                       74 cal               4 gm         all aa

Navy beans                        4 oz                         88 cal              8 gm         all aa, low in methionine + cystine

Peas                                    4 oz                      108 cal               8 gm      all aa except no trypotophan

Lima beans                         4 oz  cal                88 cal                5 gm       all aa, low in methionine + cystine

Brussel sprouts                    1 cup                    65 cal               6 gm.    low in leucine, lysine, methionine + cystine, phenylalanine + tyrosine

Spinach                            1 cup chopped        65 cal                6 gm      low in methionine + cystine

Broccoli                            1 cup spears           52 cal               6 gm      low in methionine + cystine

Potato                               1 med with skin     161 cal              4 gm     all aa in proper ratio

Asparagus                         ½ cup                     20 cal                2 gm    all aa in proper ratio

Fruits

Apricots dried                    ½ cup                   190 cal              3 gm       low in methionine + cystine

Peaches dried                     ½ cup                   185 cal             3 gm       low in trptophan and lysine

Cereal, bread, grains and pasta

Oat bran                              1 oz                     59 cal               5 gm       low in lysine

Oats                                     1 oz                   109 cal              5 gm        low in lysine

Wheat flour                          1 oz                    95 cal             4 gm         low in lysine

Spaghetti, whole wheat     dry 2 oz              198 cal              8 gm         low in lysine

Egg noodles                      dry 2 oz               219 cal              8 gm          low in lysine

Buckwheat                           1 oz                    96 cal              4 gm        all aa in proper ratio

Couscous dry                       1 oz                  105 cal               4 gm          low in lysine

Bulgur                             dry 1 oz                  96 cal               3 gm          low in lysine

Millet raw                             1 oz                 106 cal               3 gm         low in lysine

Bread, pumpernickel           1 slice                 65 cal               2 gm          low in lysine

Bread, reduced cal white      1 slice               48 cal               2 gm         low in lysine

Rice, brown long grain cooked  1 cup         216 cal               5 gm         low in lysine

White rice, cooked               1 cup                194 cal              4 gm         low in lysine

Whole wheat bread              1 slice                 69 cal              4 gm         low in all aa except tryptophan

White bread                         1 slice                 67 cal             2 gm         low in lysine

Oatmeal bread                     1 slice                 73 cal             2 gm         low in lysine

Rye bread                            1 slice                 83 cal             2 gm         low in lysine

Whole wheat pita bread    4” diameter           74 cal             3 gm         low in lysine

Pita white enriched            4” diameter          77 cal              3 gm        low in lysine

Combination suggestions

If low in lysine-  Combine with ricotta, provolone, gouda, mozzarella, parmesan, gruyere, swiss cheese, soy, tuna, salmon

If low in tryptophan-  Combine with oat bran, pumpkin seeds, sesame seeds,  black walnuts, sunflower seeds, cashews, pistachios, almonds, cod, lobster, tuna

If low in methionine + cystine, :phenylalanine + tyrosine  combine with chestnuts, brazil nuts, halibut, oatmeal, sesame seeds, oat bran, eggs

Sources and more information