Once again I am indebted to James Wong for an interesting article in his column in the New Scientist that suggests to me a blog topic. He has written an excellent piece about the nutritional value of trendy ‘ancient wheats’ compared to modern varieties. I plunder his best lines.
“variety for variety compared, Canadian wheat contains ten times as much selenium to that grown in the UK”
“ boring old flour contains twice as much manganese and fibre than most ancient wheats”
“ Much research on the claimed benefits of specialist grains is supported by growers - funny that”.
It is not my intention today to talk about all round nutrition and talk about fibre, vitamins and such things. I just want to concentrate on the minerals in our diet - and their primary source, plants from the soil.
A line I will take is that our own UK soils are not seriously nutrient depleted and my worry is that possible future legislation that will seek to improve agricultural practice in terms of acting upon issues of global warming and habitat destruction might be misdirected. I just cringe when the tv news endlessly shows that silly man who keeps preaching that for the last seventy years we have been poisoning our soils. (Nominate your own culprit, another contender was minister for the environment!)
As gardeners we consider what nutrients will make our plants grow healthily.
For certain crops farmers are also concerned which nutrients from their crop are needed by their animals. Selenium and iodine are two examples of trace elements not needed for plant growth but are paramount for the health of livestock.
We too should be concerned about mineral nutrients in the plants that we grow.
On a worldwide scale their are large areas deficient in specific important nutrients and plant breeders are working to breed crop varieties with increased nutrient uptake from the soil.
Quick check on nutrients essential for plant growth
Gardeners will be be familiar with the major nutrients NPK, nitrogen, phosphorus and potassium.
Once called minor nutrients magnesium, calcium and sulphur are now considered major too
Micronutrients, also dubbed trace elements are (in no particular order) manganese, molybdenum, iron, copper, zinc and boron.
Some other minerals are essential for specific plant species and in other cases although not essential, are beneficial. These include chlorine, sodium, cobalt, selenium and the not at all inconsequential silicon that I blogged about recently.
|Old gardeners fed their asparagus with common salt (not recommended)|
There can be massive variations in plant uptake of minerals which vary with such as soil and plant-species or variety.
It is important to note that their are very many more different minerals that plants absorb than those they require for their own nutrition
A very important point is that farmers and growers need to ensure a supply of essential minerals to get a healthy crop and it is these very same nutrients that are important in our own diet. Many modern fertilisers contain the essential trace elements and rather than being detrimental to the level of necessary minerals in our soil as is sometimes claimed, modern fertilisers are the opposite.
Reports that UK agricultural soils are depleted of nutrients and that modern vegetables contain less minerals than historically
As to the first absolutely not. As to the second maybe and sometimes
There have recently been much hyped claims that our soils and its produce are seriously mineral depleted. Over the top and out of proportion it is worthy of investigation and over the years it has been intensively and responsibly scientifically studied.
Great ingenuity has been directed in comparing past and present. It is notoriously difficult considering such things as huge differences between mineral content of one plant-variety and another, plants grown on different soils in different countries in varying conditions in different seasons and even whether old methods of analysis are the same as those done today. Much excellent and detailed research has been carried out and I recommend if you really want to really know about these things you read the link to the Elsevier article in the Journal of Food Science 2017. It is a long piece bringing stuff together.
To be honest my head hurt as I continued to read it but as an informed honest analysis it is second to none.
It accepts that there will be exceptions to any conclusions - there is so much variation the world over.
It shows in the round, that UK farm soils are NOT depleted in nutrients, indeed as the result of modern enriched fertilisers they sometimes contain more nutrients than before
In respect to whether crops contain less minerals there is sometimes a ‘dilution effect’ as modern high yields spread nutrients thinner. The effect is relatively small and by no means universal. The affects of varietal and soil differences hugely out distance such mineral depletion.
In counter to this, modern living has greatly increased the range and extended season of vegetables and fruit on our table all year round and the modern portion size on our plate is much greater.
|I pile kale on my plate|
In contrast at home Brenda insists I take my own huge helping last after visitors have taken their meagre share.
Phooey to five a day propaganda).
Do fruit and vegetables from our gardens contain more or less minerals than those from the shop? …
…and how do we maximise them?
|More manky but what about their minerals?|
We gardeners avoid many perhaps overlooked mineral deficiencies by increased use of organic matter but recycled organic matter contains no different minerals than those available from the parent soil. It will be true that nutrients are less likely to be ‘locked up’ and become more available in those soils with higher levels of organic matter but nutrients do not come from nowhere.
In contrast purchased produce might have been grown anywhere in the world and will benefit from huge variations in soil’s natural mineral content. The presence of specific trace elements might vary by orders of magnitude depending where they come from.
In a sense if all your produce is homegrown, all your eggs are in one basket. You might just win the lottery and some ‘magic nutrient' might make you live for ever! I don’t really think so.
Some minerals are potentially toxic. I wrote about what I dug up in a failing patch in an ornamental border at home. In old properties you cannot imagine what your ancestors might have disposed of. In my case it was rusting old machinery!
American blog ‘Garden Professors’ carried an article where the writer had her soil analysed in the vicinity of an old lead painted conservatory and concluded she had better not grow vegetables there. I think she might have been a bit of a hypochondriac but no need to take chances.
I believe our own retail food supplies are so carefully monitored that toxic levels of such as ‘heavy metals’ would never happen.
Do we need to supplement the minerals in our diet?
For most of us multi mineral pills are a firm no and our varied diets ensure we get what we need.
Some folk recognise that their diets are poor and are tempted ‘to make sure’ by taking pills. Take care if any, not to take too many.
Of course some people have special mineral needs such as those who have iodine, calcium and iron deficiencies and are under medical supervision to supplement them.
|Bananas are a good source of potassium|
On the downside excess common salt - a source of the minerals chlorine and sodium is a serious risk. (Down with processed food and up with fresh vegetables on your plate)
|No minerals here|
For many of us the future is likely to be almost vegetarian but with regard to lack of minerals we have little to fear.
That is not to say that there is no place for breeding crops with enhanced mineral uptakes and indeed direct mineral supplementation. Food supplementation brings its own political problems and in the UK is fairly small.
I am ever grateful that the water in Hartlepool was naturally rich in fluoride and my teeth got a good start in my early years.
As I write my post I have a morning cup of tea. Apparently it is a useful source of manganese. The other minerals do not have time to dissolve when we brew it according to research in New Zealand. The writers observed that the tea drinkers might get more (and not insignificant) nutrients from the hard water.
I curse every time I use tap water to top up my pond I get a flush of algal growth as a result of its minerals.
My old auntie swore by the benefits of emptying her tea pot onto the hydrangeas every morning.
The Elsevier article that gives you the lowdown