The dreaded protein inquisition

by Rosalind Stone

The first question you will be asked when someone finds out that you are vegan (or that you eat a 100% vegetarian diet) is “Where do you get your protein?” In fact it is the middle and last question too, and it pops up all over the place and from the most unexpected folk! People who are severely underweight and totally lacking in muscle tone because their strict calorie control has eroded away their muscle tissue; grossly obese people who appear not to care what or how much they eat; and my personal favourite “the vertically dead” – people who are supported by the medical and pharmaceutical industries, and personify poor health!

Nevertheless you will be required to justify your choice, and so you may as well have a few ready-made answers. You could, of course, say dryly “Same place as elephants, rhinos, hippos, buffaloes and gorillas” but that is likely to be met by some sarcastic response that you are none of the above.

Let us begin by understanding what “protein” is, for it is far more than the stuff that makes muscles; in fact, protein compounds make up just about everything in the body, from tissues to hormones. And there is no such thing as a “complete protein” – each protein found in the body is a chain of amino acids, arranged in a particular pattern, that performs a very specific function, and each chain is, therefore, both necessary and complete within itself.  

There are twenty amino acids altogether, and a healthy adult human being is able to synthesise 11 of these, provided that the other nine – commonly referred to as Essential Amino Acids – are consumed in adequate amounts. All of these are readily available in edible plants (and inedible plants, for that matter, but why would one want to eat something that is going to gradually kill you? Why, indeed!)

It goes without saying that the body does not take chunks of medium rare rump steak and simply load them onto the biceps, triceps, gluts or any of the other muscles; regardless of the source of protein, it is all broken down during the digestive process into separate amino acids, which are then stored within the body’s amazing storage system, neatly labelled and ready to be dispensed as soon as the RNA demands it. Through an immensely complex physiological process these amino acids are then arranged according to blueprints, to provide exactly what the body has requested.

Since we now understand that the amino acids are stored in the body for later use, it stands to reason that we don’t necessarily have to consume all 9 of the Essentials in a single meal, as long as we are eating a varied diet. Baked beans on wholewheat toast, or beans and rice, will provide the 9 essentials, but we can have the beans for dinner and the toast for breakfast and the body will take what it needs.

Before we look at the actual “protein value” of various foods, it is important to know that there are three basic methods used to measure this.

The Protein Efficiency Ratio (PER) which was based on the amino acid requirements of growing rats, noticeably different from humans, and therefore now pretty defunct.

The Biological Value (BV) which uses nitrogen absorption as a basis, but fails to consider factors influencing the digestion of protein, and ultimately measures the potential protein quality, rather than the actual bio-availability.

The Protein Digestibility Corrected Amino Acid Score (PDCAAS) - a method of evaluating the protein quality based on both the amino acid requirements of humans and their ability to digest it. This is the most recent method of evaluation, adopted by the FDA, FAO and WHO, as the most reliable.

A shortened list of the PDCAAS findings follows, with a score of 1 being high, and 0 the lowest. It should be noted that some concern has been voiced about the fact that the four foods scoring 1 have totally different amino acid profiles, and would therefore perform differently in the human body, and this casts some doubt as to the usefulness as a comparative tool. Another limitation is that there is no way of knowing whether the protein has been digested by the body, for the body, or whether it has been broken down in the digestive tract through bacterial activity. It is, however, generally accepted that amino acids are less likely to be absorbed for synthesis as food moves further down the digestive tract, and that plant-based foods are digested faster and therefore higher in the gut. Animal protein, particularly flesh, is digested very slowly and begins to putrefy which involves heightened bacterial activity.

• 1.00 casein (milk protein)
• 1.00 egg white
• 1.00 soy protein
• 1.00 whey (milk protein)
• 0.92 beef
• 0.91 soybeans
• 0.78 chickpeas
• 0.76 fruits
• 0.73 vegetables
• 0.70 Other legumes
• 0.59 cereals and derivatives
• 0.42 whole wheat

One must remember that gram for gram, plant-based foods contain higher levels of other macro- and micro-nutrients, as well as fibre, and fewer potentially harmful substances, and therefore offer greater health benefits.
Nonetheless there are those who will argue in favour of one or the other, so I have attempted to throw the results from all of these studies into a huge melting pot to reach a “probable mean average” - no doubt a term that will have the actuarial scientists and biochemists in a complete knot!

The scribblings on my jotter pad produced these results (grams protein per 100g) which compare very favourably with the results of each of the above methods:

Veal & Beef: 16 – 40g/100g (depending on the butchers cut)
Poultry, Lamb, Pork: 30g/100g
Fish: < 30g/100g
Egg: 11g/100g
Dairy Milk: 4g/100g

With all the cholesterol, antibiotics, hormones, adrenalin and horror, as opposed to:

• Beans: 32g/100g
• Pumpkin seeds: 33g/100g
• Peanuts: 24g/100g
• Lentils (raw): 26g/100g (sprouted)
• Lentils (cooked): 9g/100g
• Nuts: 20g/100g (average, depends on variety)
• Fruits & Veg: 2.5g/100g (very much an average)
• Spirulina: 66g/100g (average depending on source)

It’s fairly obvious that a plant-based diet provides very adequate amounts of protein, especially when one considers that it is easily digested and quickly absorbed into the body. Also interesting that Spirulina has the highest value of any of the tested foodstuffs, so may be a good supplement to add to your Vitamin B Complex if you are concerned, and particularly for growing children.

Furthermore not all proteins are equal: studies reveal that rats who had been exposed to cancer-causing substances, and then fed a diet of whey protein developed cancers and died.  However those who were fed a plant-based high protein diet did not, even when the actual protein intake was substantially higher. Animal proteins are extremely acidifying and promote various chronic diseases (read The China Study by Colin Campbell for in depth info on this subject).

Another interesting little fact to have up your sleeve is that most of the worlds leading experts on athletic training agree that the only thing that really stimulates the body to build muscle, is exercising! According to Dr. Douglas Graham, "In reality only weight-bearing exercise builds muscle. When insufficient carbohydrates are supplied, it is true that protein requirements go up, as the body transforms the protein into carbohydrate (an energy-expensive process) and utilizes it for fuel. This does not, however, bring about the result (body builders) desire." What’s more, excess protein is converted into body fat! In short, if you want that lean, mean body – eat adequate protein and enough carbohydrates to sustain your exercise regime, but most importantly – do the training!

Which brings us to the question “How much protein do we actually need?” Although there is no absolute consensus on this – for obvious reasons, depending on your level of activity and whether you are still growing or just maintaining, or perhaps growing sideways rather than upwards -  the current recommended daily intake (RDI) of protein is 46 grams for women aged 19–70 and 56 grams for men aged 19–70. (In my humble opinion the age spread in this casts doubt on its accuracy, not to mention that the requirements of a very active 120kg Springbok rugby player must be vastly different to a 70kg office worker, purely from the perspective of percentage of body mass!) Any excess protein consumed is turned into energy by the body, and it is controversial whether this excess protein causes a strain on the liver. What is not required for energy, is stored as fat.

In a nutshell, a diet consisting of a variety of fresh fruit and vegetables, with some nuts, beans, grains and legumes tossed in for added texture and flavour, will provide all the protein your body requires.

I will give the final word to Dr Colin Campbell who says "The concept of quality really means the efficiency with which food proteins are used to promote growth. This would be well and good if the greatest efficiency equaled the greatest health, but it doesn't and that's why the terms efficiency and quality are misleading. In fact...there is a mountain of compelling research showing that "low-quality” plant protein, which allows for slow but steady synthesis of new proteins, is the healthiest type of protein...Plant proteins may be lacking in one or more of the essential amino acids, but as a group they do contain all of them."

Be a living example of what you believe – exuding good health and vitality is the best response to any interrogation about your dietary choice.

So above all, Do No Harm - to your body, the planet or any sentient being!