Protein, an indispensable part of our diet, has multiple roles in the body – particularly in aging for growth, repair and maintaining muscle mass. But dietary proteins are not all equal. Here are some nuts and bolts of this exquisitely complex nutrient.
Protein, carbohydrate and fat are all macronutrients formed by different ratios of carbon, hydrogen and oxygen. Additionally, protein contains nitrogen.
Proteins come in all shapes and sizes. They are created from twenty amino acids joined in fifty to tens of thousands of different combinations to make enzymes, antibodies and hormones, transport molecules and regulate the body’s acid-alkaline balance.
Nine amino acids are essential – the body cannot make them, so they must come from dietary sources. These are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Six amino acids are conditionally essential (needed in special circumstances like illness) and five are dispensable as the body can synthesise plenty of them.
The biological activity and nutritional benefits of protein vary according to how the amino acids are configured and how the body digests them. Based on this, various methods have been devised to measure protein quality – availability of its amino acids – and digestibility – how the protein is best used.
The biological value (BV) scoring system assumes that protein is the only dietary source of nitrogen. It measures protein quality by calculating a ratio of how much nitrogen is absorbed versus the amount excreted then multiplied by 100 to give a percentage of nitrogen used by the body.
The protein digestibility-corrected amino-acid score (PDCAAS) ranks protein quality by comparing its amino acid profile with a reference score, corrected for faecal nitrogen digestibility. This score was backed jointly by the Food and Agricultural and World Health Organisations (FAO/WHO) in 1989 as the best way to assess protein quality.
But the PDAAS has limitations; for instance measuring amino acid synthesis in the small intestine would be a better assessment of their digestion than in the large bowel (colon). Further analysis has suggested that the PDCAAS tends to underestimate high-quality proteins and overestimate low-quality proteins.
The FAO now recommends the digestible indispensable amino acid score (DIAAS), which measures the digestibility of individual amino acids at the end of the small intestine and may therefore be more accurate.
Despite some variation, the quality ratings generally agree on high protein food sources. Animal protein contains all the essential amino acids and is therefore complete. Eggs and dairy protein are ranked as high-quality proteins, followed by meat, chicken and fish. Eggs and dairy are easily digested and are good options for people with digestive disorders.
Vegetable protein typically lacks one or more amino acids. But the following combinations provide all essential amino acids and are therefore highly ranked: rice and peas; grains and legumes; grains and vegetables; grains, nuts and seeds; legumes, nuts and seeds. Importantly, the body doesn’t necessarily need all amino acids in one meal – they can be spread out over the day.
Some vegetable proteins do contain all essential amino acids. This includes hempseed, pea protein and quinoa.
This is good news in light of mounting research showing the superior health benefits of a plant-based diet. Plant foods provide fibre and nature’s medicinal cabinet of vitamins, minerals and phytonutrients. Concerns over ethics of animal farming and environmental sustainability are also driving a growing demand for diets higher in plant foods.
Cannabis, or marijuana, is the world’s most highly used illicit drug. But hemp – although it derives from the same species – will not cause giggle fits, big toenail fascination or insatiable pizza cravings.
Hempseed contains only negligible amounts of marijuana’s primary psychoactive compound, tetrahydrocannabinol (THC) – and its high concentration of cannabidiol (CBD) counteracts THC’s brain-altering effects.
A diverse, fast-growing plant, hemp is used industrially to make numerous products including paper, canvas, linen, clothing, biodegradable plastics, paint and insulation.
And hempseed – legalised in Australia November last year – has been eaten for thousands of years raw, cooked and roasted. Technically a nut, it is packed with nutrients that include healthy omega-3 and omega-6 fats, vitamin E, minerals, fibre, and protein.
Rivalling whey powder’s 13% protein content, hemp contains 25% protein – more than chia seed and quinoa. Hempseed contains 20 amino acids. That includes the 9 essential peptides that humans need from dietary sources, making it a complete source of plant protein.
The protein is also easily digested, making it highly bioavailable. Its protein digestibility-corrected amino acid score (PDCAAS) is “equal to or greater than certain grains, nuts, and some pulses,” according to researchers from the University of Manitoba.
Research suggests hempseed protein has several health benefits including reduced fatigue and improved immune function. Hempseed protein may also lower blood pressure and cholesterol, indicative of heart health benefits. Its antioxidant properties reduce free radicals responsible for accelerated aging.
In aging, good quality protein itself is important for retaining healthy muscle mass and bone density to reduce risk of sarcopenia and osteoporosis. It can lower risk of falls and improve recovery and wound healing. Protein may even help ward off diabetes and dementia.
Since its legalisation, industry has been creatively devising new products to deliver hemp seeds’ nutritional benefits to consumers – including hemp beer, hemp chocolate and hemp oil. It is also available as a protein powder and flour for baking.
Hempseeds have a nutty flavour. Recipes have sprung up to include them in a smorgasbord of foods ranging from granola, hummus, burgers, pesto, protein balls and chutney to bread, soup and smoothies.
And hemp is not just good for us; it is ecologically sustainable. As well as being fast growing, it does not need much water, so is an ideal crop for Australian conditions. Harry Youngman, Victorian farmer, told the ABC that its “water use efficiency is incredible.”
With its “aggressive rooting structure,” it helps to break up the soil, making it an ideal rotational crop between seasons. Even better, it is weed-resistant and needs little, if any chemicals.
Popeye devoured spinach to make his muscles strong. But his creators, like everyone else, were duped by a chemist’s miscalculation of this vegetable’s iron content. Could coffee have helped?
Many athletes drink coffee not just for a pick-me-up, but to help them perform. Sports scientists have explored caffeine’s exercise enhancing properties for more than a century.
More recently, the focus has shifted from aerobic exercises like cycling and running to caffeine’s effect on muscle strength, power and endurance.
Studies have found varying effects of caffeine on muscle performance. One meta-analysis – larger analysis that pools all eligible studies together – found that caffeine increased the lower body’s muscle contraction ability by 7%. However, another meta-analysis found no effect. Part of the reason could be the type of tests that were used.
A new meta-analysis of ten studies has now reported that caffeine improves muscle strength and power using one-repetition maximum and vertical jump tests, respectively. Curiously, further analyses found that caffeine improved upper but not lower body strength.
Scientists are not clear exactly how coffee might enhance performance, but evidence suggests its effects could be multifactorial. It seems to revolve around caffeine’s stimulation of the nervous system. This likely explains why it helps people feel more alert. Caffeine may improve performance by enhancing muscle contraction and subduing perceived pain and exertion.
Maintaining muscle mass and strength is particularly important for healthy aging. Strength training programs tailored to individual needs, supplemented by protein and good nutrition, will alleviate risk of sarcopenia, falls, hospitalisation and associated decline.
It’s important to note that statistical analyses of research outcomes work on averages. Caffeine research shows notable variation in people’s response to it. This variation is apparent in research on its heart and cognitive benefits.
A study published last month reported that a large pooled analysis of several population-based studies showed caffeine intake was associated with decreased atrial fibrillation (abnormal heart rhythm that can impact heart function). Up to 6 cups of coffee a day was not linked with increased severity of abnormal heart rate overall. But around a quarter of patients reported that coffee did trigger atrial fibrillation.
People’s muscle function also shows varied response to caffeine. One study, for instance, reported that some participants’ back-squat performance decreased by 7% with caffeine intake while others increased by up to 10%. Authors concluded that, “Due to inter-individual variability in responses to caffeine consumption, it must be used in an individualized manner.”
The authors noted that people are likely to be caffeine ‘responders’ or ‘non-responders.’ In this they refer to genetic differences. People who are slow caffeine metabolisers lack a gene that is seen in fast caffeine metabolisers – you know, those lucky people who can have a coffee at midnight and still sleep soundly.
It turns out that positive links between coffee and heart health are seen in fast, but not slow, coffee metabolisers.
So if you know you can happily tolerate caffeine, indulging in a cuppa before exercise might help boost endurance and build muscle – perhaps not quite like Popeye but stronger and healthier nonetheless.
As we face a burgeoning aging population, food quality in aged care has entered the limelight. After all, nutrition is pivotal for good health and healthy aging. Food also enhances quality of life through the joy of eating and the social interaction that it fosters.
Yet more than half of Australian aged care residents suffer or are at risk for malnutrition.
Malnutrition carries a host of negative outcomes like increased risk of falls, osteoporosis, arthritis, poor recovery from illness, delayed wound healing, depression and mortality. It lowers quality of life. And it is preventable.
It’s not just a matter of ensuring all nutritional needs are met, which include protein, energy and a variety of foods from each food group. Several other considerations factor in.
Improving older people’s nutrition status would need a multifactorial approach to address problems with swallowing, dentition, food packaging, eating support, appetite, food preferences, taste and environment.
Fundamentally, quality food needs higher priority in aged care budgets.
Even though people and organisations like Maggie Beer, Nutrition Australia, The Lantern Project and others are tackling this issue, systemic change may only come with mandatory guidelines.
Services provided at residential aged care facilities are regulated under the Aged Care Act, through the Aged Care Standards and Accreditation Agency. The standards include general nutrition information, but no mandatory guidelines for nutrition and menu planning. Hospitals have standards, so why doesn’t aged care?
To rectify this situation, mandatory nutrition standards would need to be created, implemented and enforced for all Australian aged care facilities.
The new standards could contain the following recommendations:
The residential aged care landscape is fragmented. Cooperation among all stakeholders would be imperative for the successful creation, acceptance, adoption, rollout and continuation of new mandatory standards.
Stakeholders include the government’s Australian Aged Care Quality Agency, My Aged Care program, Residential Aged Care Facilities (RACFs), Leading Aged Services Australia, Dietitians Association of Australia, and Speech Pathology Australia.
Challenges would need to be ironed out. Thousands of aged care workers complain about cost cutting, understaffing and rationing in RACFs, resulting in “struggle to provide the most basic level of care and dignity for elderly people.”
Clearly, a cultural overhaul in aged care facilities would be essential for a new mandatory policy to succeed. This could be achieved through collaboration with stakeholders, priority budgeting, and a directive issued from above: the government body responsible for aged care quality.