Perils of excess protein and supplements

Sunil Prakash

PROTEINS are the building blocks of our body. They contain nitrogen, which is unique to them, as other food constituents like carbohydrates and fats do not have nitrogen. The average recommended requirement of protein in persons with a sedentary lifestyle varies from 0.6 gm to 0.8 gm/kg body weight. A person weighing 60 kg will need 36 to 48 gm protein per day for enabling her/his body tissues to repair and restore to normalcy. Children, pregnant women and lactating mothers need more dietary protein between 1 and 1.2 gm/per kg body weight.

Protein deficiency is quite common in India and much of it has do with the cost involved in the food intake. Inadequate intake of protein leads to malnutrition. In children, it causes growth retardation and wasting diseases like marasmus (severe undernutrition causing wasting of fat and muscle under the skin) and kwashiorkor (severe protein malnutrition that causes fluid retention and a swollen, distended abdomen).

In pregnant women, the deficiency can lead to intra-uterine growth retardation (IUGR), affecting foetus growth and other complications, including embryonic death and reduced postnatal growth. On the other hand, high maternal dietary protein intake can also result in IUGR and embryonic death. This is due to amino acid excesses or toxicity of ammonia and homocysteine (can cause damage to artery lining, leading to blood clotting, raising risk of coronary artery disease, heart attacks and strokes) that are generated from amino acid catabolism.

Protein intake is increased usually on two accounts.

People desirous of weight loss follow high protein and low carbohydrate diets like Atkins in which 30 to 35 per cent calories are provided by protein breakdown. These diets cause weight loss but there is a propensity to develop severe side-effects like ketosis (body burns fat for energy instead of glucose), especially if these diets are taken in an unregulated and unsupervised manner.

People who want muscular bodies or are into body building indulge in more dietary protein intake. Excessive intake is usually defined as consuming more than 1.5 gm protein/per kg body weight. People into body building may end up taking 2 to 3 gm proteins/per kg body weight.

Various studies have linked excess protein intake and the progression of renal disease. One study linked increased animal protein consumption to a decline in renal function.

High dietary protein intake can lead to hypertension inside the small fragile vessels of kidney called glomeruli. High intake causes injury to the glomeruli, leading to intra-glomerular hypertension (IGHT). The glomeruli are extremely fine sieves that separate the waste metabolic products in the kidney. They return essential components back to the body and throw out all waste products like urea, urates, creatinine, metabolic acids and hundreds of potentially deleterious compounds. Once these extremely delicate glomeruli are injured, they cause increased albumin or protein loss in urine. This is called proteinuria/albuminuria, early indicators of kidney damage. Rising IGHT and proteinuria invariably leads to progressive renal failure. If left unattended, the patient may need regular dialysis and or even kidney transplant.

Animal proteins release more nitrogenous waste, metabolic acids, phosphates and many others compared to plant-based proteins. Therefore, in patients of chronic kidney disease (CKD), plant-based proteins are preferred over animal sources. Substituting one portion of red meat with legumes can reduce the risk of CKD by 31 to 62 per cent.

Gym-goers opting for protein supplements should be careful and take professional advice to regulate their intake. Many supplements contain unsafe excipients and other chemicals in the protein packs which are nephrotoxic (cause rapid deterioration in kidney function as a result of medications and chemicals). Their usage has led to a particular kidney disease called gym nephropathy.

Symptoms

Excessive protein intake is known to cause hypertension and kidney damage, especially in people having kidney disease, however mild it may be. Ironically, there may be no symptoms and signs of kidney damage as chronic kidney disease is mostly asymptomatic in early stages. As the disease becomes chronic, it may cause hypertension, especially at extremes of age, anaemia, bone aches and pains, infertility, paradoxically passage of more urine, especially at night. The patient may be asymptomatic and may come suddenly with advanced kidney damage, requiring dialysis and/or kidney transplant.

Animal sources vs plant sources

• All natural sources of protein are safe. However, synthetic protein supplements may be laced with impurities, which can cause gym nephropathy.
• Animal proteins have all nine essential amino acids. Vegetarian proteins lack some amino acids. However, when eaten in combination like daal-rice or wheat bread with peanut butter, it becomes complete protein.
• Bodybuilders usually consume more animal proteins as it contains lysine, which stimulates muscle growth. Animal proteins produce more phosphorus and other nitrogenous waste and put more load on the kidneys. In healthy persons, it is a non-issue but in hypertensive and kidney patients, it may worsen kidney functions.
• Excessive red meat consumption can cause atherosclerosis, leading to heart attack and brain-stroke risk.

— The writer is HoD, Nephrology, BLK-Max Super Speciality Hospital, New Delhi