So many times I have people ask “Can’t I get everything I need from eating more fruit and vegetables?” It’s a misunderstood area in nutrition. All of us grew up believing that if we ate a reasonable diet, that would take care of our vitamin needs. But the evidence now shows that not to be the case.
Much of the produce we eat today contains lower nutrient levels than that from our parents’ and grandparents’ days. This makes it much harder to get optimal nutrition from food alone.
mineral density of soils
Our physical health ultimately depends on the health of our topsoil. Plants provide us with important micronutrients: vitamins are manufactured by the plant and minerals are absorbed from the soil. If important minerals are depleted in our soils, our bodies are also deprived of them.
Unfortunately our soils are missing important nutrients.
Firstly, nutrients aren’t in the soil to begin with. It is well known that New Zealand soils are deficient in iodine, selenium, zinc, chromium and boron. The mineral density of soils is dependent on the rock bed, and the breakdown and release of those minerals into the soil. New Zealand is a young country geologically, with young soils that are therefore not as dense in minerals.
Second, to keep up with food demand, land is being farmed intensively. In doing so we’re stripping nutrients out of the top layer of the soil and farmers aren’t putting trace minerals back in.
USE Of Fertilisers and Pesticides
Most farmers are focused on increased yield, which exacerbates the issue further. When nitrogen fertiliser is used to speed up growth, this also results in plants having a significantly smaller root structure, heavily limiting the plant’s access to nutrients.
To increase the yield of crops, farmers often spray with chemicals to kill pests, diseases and weeds. As well as the obvious concern over these toxins then entering our bodies, the use of sprays also results in lower levels of antioxidants in our fruit and vegetables. Chemicals in sprays basically take the place of plants’ own protection mechanisms so they no longer need to produce antioxidants themselves. One study I’ve seen indicated that a switch from conventional to organic crop consumption would result in a 20-40% (and for some compounds more than 60%) increase in crop-based antioxidant/(poly)phenolic intake levels.
I highly recommend buying organic or spray free produce.
Cold Storage & Artifical ripening
The conditions fruit is ripened in affects the quantity of antioxidants it contains. When fruit is left to ripen on the tree, nutrients continue to accumulate. For example, tomatoes – ripened on the vine – have significantly more lycopene and beta-carotene.
However these days produce is often picked early (once it’s mature but before it’s really ripe) and ripened off the tree, except for non-climacteric fruits such as cherries. Often ripening is halted – until demand necessitates – via cold storage and sometimes dropping the oxygen level. Cold temperatures slow down the ripening process by slowing the chemical conversion of starch to sugar. Dropping the oxygen level essentially prevents fruit from breathing (and aging).
But – when the time is deemed right – ripening doesn’t develop exactly the same way off the tree as it does on. Research is still being done in this area to understand the reasons why. Complexity of flavour is a good indicator of nutritional content. And you can’t beat a ripe tomato, picked just off the vine… compared to an out-of-season tomato purchased at the supermarket.
days from field to plate
Produce loses some nutrients after harvest. The number of days ripe fruit and vegetables take from field to plate, the more of its nutrients will be lost. Green beans typically take 11-15 days before they reach your mouth with 45% of key vitamins lost; carrots typically lose 10% over 9-10 days. And you can’t necessarily tell by looking at it – produce starts looking bad even before it begins to lose nutrients significantly.
If you don’t grow you own and pick the day of eating (I can for some produce but am definitely not self-sufficient), I recommend buying in season and locally; local farmers markets are a great option, with items more likely to have been picked recently.
And an extra tip, the best way to store fruits and vegetables is to leave them unwashed with the skin or rinds intact until the day you plan to eat them. Less surface area means less oxygen exposure and more vitamin retention.
We must accept the fact that foods – fruits, vegetables and grains – no longer contain enough of certain needed nutrients, starving us – no matter how much we eat of them. (Plus despite our best intentions to eat a balanced diet, its extraordinarily difficult to do so with our modern lifestyles and the availability of processed food thrown into the mix as well).
That is why daily supplementation with a high quality, broad-spectrum nutritional supplement – one with a full range of necessary vitamins, minerals and plant-based antioxidants – is a wise preventative measure to reduce the risk of chronic disease and promote long-term health.
A final point: eating a healthy diet is a necessary foundation for any program of supplementary nutrition. Supplements are designed to complement a healthy diet, not replace it.