Food as a source of nutrients

How do we ensure our diets are providing the key nutrients for ‘normal everyday’ functioning? For a food to deliver optimal nutrients it must be nutritionally rich when consumed.  The issue here is that health benefits derived from consuming food will be compromised by any time gap that arises between the moment a food is picked or produced and its consumption.  Nutrient losses can occur between harvesting, during processing and distribution as well as during storage.   To ensure the food we consume is at its most nutritionally ‘active’ we should choose food that is, in an ideal world, organic, free-range (where appropriate), grown in nutrient rich-soil, locally sourced, freshly picked and optimally stored.  Many nutrients are also highly influenced by cooking so consuming food raw where possible will certainly help retain vital nutrients.  We also should avoid foods that are either processed or refined, as these steps are known to strip them of key nutrients either by direct removal as part of the process or through loss due to sensitivity to heat, light and oxygen.  Many cereals, for example, require fortification with key nutrients to avoid deficiencies that may arise as a consequence of processing methods.  If we follow these simple rules it is highly likely that we will meet our RDA.  But then….there are additional influential variables that may influence nutrient uptake. Phytates and oxalates are, for example, antioxidant compounds found in whole grains, legumes, nuts and seeds (and those cups of tea you drink!). The issue with these compounds is that they bind to certain dietary minerals including iron, zinc and manganese and, to a lesser extent, calcium, and slow or inhibit their absorption.   So the message here is that there’s a lot to think about when considering how to optimise nutrient intake and avoid potential avenues that may give rise to sub-optimal nutrient levels. 

There are individuals, those of economic restrictions, those with poor food choices or those with higher nutrient requirements (as in some disease states), for example, where levels of certain micronutrients may not be met from food alone. For example, vitamin D deficiency is a growing concern and NHS figures suggest that the number of under-18s who have been admitted to hospital in England for rickets has soared by 25% in the last 9 years.   As such, the government’s chief medical officer Dame Sally Davies has recently suggested that all low-income families and all children under the age of five receive free vitamin and mineral supplements to help reduce the growing incidence of nutrient-deficiency related conditions. 

For many of us, supplementing the diet with multivitamins and minerals is seen as merely a method to ‘top-up’ our levels of nutrients that we feel may often be missing from our normal diets.  Vitamins and other dietary supplements are not intended to be a food substitute and they cannot replace all of the nutrients and benefits of whole foods.   There may be occasions or lifestyle changes that can increase our nutrient needs or influence absorption from food sources, thus warranting popping the odd multi-vit.  Some drugs can impede absorption, for example, corticosteroids, often prescribed to reduce inflammation, decrease absorption of calcium and vitamin D.  Long-term stress can result in the body being on constant, low-grade ’fight or flight’ status, which can influence digestion and absorption of nutrients.  Regular alcohol and coffee consumption can also decrease absorption rates and exercise, whilst good for the body and mind, can actually increase the body’s nutrient requirements.

For those that do choose to supplement, quality is usually reflected by the price.  Ensuring the active ingredients are in bioavailable forms will significantly improve any potential health benefits.  Chelation, for example, involves attaching a mineral to an amino acid so that the body can more easily absorb it.  Chelated magnesium such as magnesium citrate is significantly more soluble and bioavailable than the oxide form which is often found in many cheap, poor quality health supplements.  So when choosing a supplement, a little research goes a long way and if in doubt about what to choose, your friendly nutritionist or health store can provide invaluable information.

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