As parents we often worry that our kids are getting enough protein. But has this essential nutrient been overemphasised?

Over the next few blogs we are going to explore how much is needed, and what happens if we have too much (spoiler alert – it affects bone mineral density, cardiovascular, and kidney health).

Kids often don’t like the texture of meat, or refuse to eat the nutritious meals we’ve put on the table – so we try to fill them up with dairy, and grains, or hide lentils in meals!

But how much protein do we actually need? and is too much a bad thing?

For an adult – we would say that the dietary protein needs over a day are equivalent to around 0.5-1g per kilogram of body weight. So a 60kg person would need between 30-60gm of protein daily – depending on how active they are. Someone who is exercising will need higher amounts than someone who is sitting at a desk for example.

Below are some common foods, and their protein content

• 1 large egg contains 7gm protein
• 2 slices of cheese contains 10gm protein
• 100gm yoghurt contains 10gm protein
• 1/2 cup of cooked oats contains 7gm protein
• 100gm of tofu contains 12-15gm protein
• 1 cup of cooked quinoa contains 8gm protein
• 2 slices of wholegrain bread contains 12g protein
• 1 200gm piece of steak contains 60gm protein!

For a child, this measurement differs with age – newborn babies have difficulty processing protein in the first weeks of life, but their kidney capacity improves around 4 weeks – although isn’t fully mature until after 44 weeks.

At 6 months of age, with so much growth and development going on, their average protein need is more than that of an adult – 1.2gm/kg of body weight, and this declines to 0.8gm/kg at age 10.

Infants under two have a reduced renal capacity to excrete acid – as their kidneys are immature and cannot process it as quickly. This is even more pronounced in premature and small babies. Breastmilk is perfectly balanced to accommodate this – whereas formula unfortunately creates an acidic load for the kidneys. And as we’ve seen above newborns have the hardest time processing this, so if possible, breastfeeding for at least the first 3-4 weeks will help immensely.

So why does this matter?

Well in infants, if the acid load is greater than they can manage, you may see reduced weight gain, impaired bone mineralisation, and interference with important renal hormones.

Australian toddlers to teens (2-12 years old) – are consuming on average 67gm of protein daily! Thats a lot when you think a 60kg adult would need 60gm or less for the day, and most 2 years olds weight around 12-15kg, and 10 year olds around 30kg. So they are having much more than their daily requirement. (Australian teens (14-18yo) are having more than 100gm daily! but thats for another blog…)

Where are they getting this from?

The primary sources of protein at this age are grains, dairy, and meat. These are all high in phosphorous which makes them acid forming. (Which doesn’t mean they aren’t nutritious, or required – just that we need to ensure they’re balanced).

Soft drink is also very high in phosphorous. Check a can of coke and you’ll see phosphoric acid as an ingredient – this is what provides us with that refreshing mouth feel, but requires lots of sugar to counter the acidity.

Why should we care at this age?

The toddler to teen age group is so important as we gain most of our adult bone mass by 14 years of age. If we are feeding our kids an acidic forming diet, that is going to directly effect their ability to form healthy bone, as calcium is drawn out of bone to buffer the acidity. So the emphasis on eating calcium rich foods for bone health is not taking into account that some of these calcium rich foods are actually contributing to bone LOSS.

Equally – with a can of coke, when drunk, the acidity of the blood increases, calcium is drawn out of the bone to lower it, and our bone mineral density pays the price.

We often don’t think bone loss will affect us until we are old – we’ve all heard of osteoporosis, but that doesn’t happen to young people does it? Think again. I will have my sister share her story of spinal fractures, and an osteoporosis diagnosis in her 30’s, in a future blog.

I’m going to say something controversial now – but stick with me:

The most important foods for bone health are fruit and vegetables.

Multiple studies have shown that a more alkaline diet is the key factor to protecting bone density, regardless of calcium intake.

How and why??

Well fruit and vegetables are high in potassium – which is the alkalising factor we need to balance out the acidity of protein.

So… The upshot of this is – everyone, kids included, need to eat a diet high in fruit and vegetables, and with adequate, but not excessive amounts of protein to ensure their bone is protected, kidney damage is prevented, and the cardiovascular system doesn’t suffer.

The next blogs will explain why dairy isn’t always best for bone health, and simple ways to ensure our kids are getting enough fruit and veg to balance their protein intake.

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Questions???