How much protein do we need to maintain healthy muscle mass as we get older?
Think you mainly need protein to build bulging biceps or keep your pecs in perfect order? Think again. This important macronutrient does a lot more than just fuel your muscles — it's essential for many aspects of your health.
A number of different functions in our body need protein, said Rosilene Ribeiro, a dietitian at the University of Sydney. We do use it for building and maintaining muscle mass, but also for producing hormones, and even sometimes as a source of energy. The main thing people don't realise, said Sandra Iuliano, a nutritionist at the University of Melbourne, is that every part of us is made from protein. "Our skin, our muscles, our hair, everything," Dr Iuliano said. "So if we don't have enough protein then those body organs aren't going to work properly." Protein is made up of different amino acids, nine of which our bodies can't make so we have to source them from food. Our bodies also can't easily store protein, which is why we need to get it from our diet every day. But the macronutrient's reputation as a nutritional all-rounder has meant many of us overestimate how much of it we actually need. "People think that we need a lot more than we actually do, and we put a lot of stress on eating protein, especially when we get older," Dr Ribeiro said. According to the Nutrient Reference Values for Australia and New Zealand, the average adult needs about 0.8 grams of protein per kilogram of body weight. It's a little less for the average woman and a little bit more for the average man, because men usually have bigger muscles. For someone who weighs 75 kilograms, this is about 60 grams, or the protein you might get from four or five large eggs, although we're sure you can come up with a more interesting menu than that! Growing children, pregnant and breastfeeding women need a bit more protein in their day. And once we reach 70, our recommended daily protein intake rises to about 1 gram per kilo. However the average Australian actually consumes around 1.2 grams of protein per kilo of body weight, said Dr Ribeiro, so most of us are getting more than we need. What happens as we age?
As we age the ability of our body to respond to protein decreases, said Dr Iuliano. "If protein comes along in a young person they can knock quietly at the door and the muscle responds, but if it's an older person we probably have to knock a lot harder," she said. "So more protein has to be there in order for that muscle to respond."
From about the age of 50 we also start to lose some of our skeletal muscle — that is, the muscles we use to move our bodies, as opposed to the involuntary muscles in our heart or gut. This natural decline in our muscle mass and strength is called sarcopenia. It's primarily due to age but can also be exacerbated by chronic illness, poor diet and lack of activity. That's why it's worth being more aware of exercising and how much protein you're using in your 50s, even if you don't have to up your intake just yet. How much protein you need also depends on your overall health circumstances. "If you're frail and sick then chances are that you are losing a lot of muscle mass because you're spending a lot of time in hospital," Dr Ribeiro said. "That's when you will need more protein because you want to protect the muscle and maintain it." The European Society for Clinical Nutrition and Metabolism has recommended people over 65 who are malnourished or at risk of becoming malnourished due to illness should aim for 1.2 to 1.5 grams of protein per kilo of body weight, along with daily physical activity or exercise.
Keeping protein in proportion with fat and carbs
Another way of thinking about how much protein you should consume is thinking about how much of the total number of kilojoules we're eating each day should be coming from protein versus fat and carbohydrates. "You want to have 15 to 25 per cent of the energy coming from protein, and then up to 35 per cent from fat and up to 65 per cent from carbohydrates," Dr Ribeiro said. This is known as the acceptable macronutrient distribution range, which aims to reduce our risk of developing chronic diseases while still ensuring we're getting enough micronutrients for good health. If you're eating the right percentage of protein as part of your diet each day, you'll meet the recommended daily intake, Dr Ribeiro said. On the flipside, consuming too much protein can be bad for our health, including by putting unnecessary strain on our kidneys and liver. Emerging research suggests it could also shorten our lives. What does all this look like on a plate?
We can either get protein from animal-based sources like milk, cheese, yoghurt, eggs, fish, poultry and lean meat, or plant-based sources like seeds, nuts, beans, legumes, grains and cereals. The difference between the two groups is that animal sources have the complete set of the nine essential amino acids our bodies can't make on their own, whereas individual plant sources often don't.
A way around this is to combine plant sources of protein, Dr Iuliano said, particularly for people following vegan or vegetarian diets. "If I put my legumes and my grain together I get all the amino acids I need," she said. "Baked beans on toast are an example." Dr Ribeiro also encourages people to not just go for the obvious sources of protein. "I do encourage older individuals to eat beans and lentils and things like that because they are cheaper, and they are healthy, and they are great protein sources," she said, as well providing additional vitamins and fibre which are good for your health as well. But she urges people to avoid processed meats like salami and ham, except as an occasional treat. "It has protein but it's got so much other stuff that is not good for you, such as sodium and saturated fats." And opt for food over supplements to meet your protein requirements, said Dr Iuliano, because of the additional benefits that come with it. "[With] food I'm getting all the other nutrients I need with it as well, it tastes better and it's probably a cheaper source." How to get protein at every meal
Here are some suggestions to make sure you're getting protein at every meal.
Breakfast could be cereal and milk, or porridge with some milk or yoghurt and nuts.
Lunch could be a salad or sandwich with lots of vegetables and maybe some lean meat, tofu or quinoa mixed in with your salad or sandwich.
Dinner could be a cheese omelette, soup, stew or perhaps another salad with some chicken or lean meat in it.
For snacks opt for things like yoghurt, nuts or perhaps some vegetables with hummus.
"The best thing about having it throughout the day is that one, you will meet your requirements, but also you'll feel satisfied and you won't feel sluggish," Dr Ribeiro said. "You don't need to eat crazy amounts of protein just because you're getting older."
Article from ABC Health & Wellbeing