It can be tricky to identify nutrient deficiencies because it’s not just about what we eat on a day to day basis. It’s about our genetic make-up, our mother’s nutrient status during pregnancy, our digestion and ability to absorb nutrients too. It is also about our exposure to anti-nutrients in our lifestyles and environments. If you exercise a lot and sweat a fair amount during this then you may have a higher need for magnesium. Likewise, if a child consumes a lot of sugar, fruit juice or starchy carbs then they will have a higher need for the nutrients that process sugars.
Are blood tests accurate?
A trip to the GP is usually the first call when wondering if you have nutrient deficiencies. A GP will run a blood test, which in the UK typically looks at iron markers, B12 and possibly vitamin D (if this is requested). Sometimes blood markers for calcium are included too. However, blood levels of nutrients are not always the most reliable indicator of what is actually being taken up and used at a cellular level. For example calcium levels in the blood are always kept within a certain range. The body will draw calcium from the skeleton to keep calcium levels within this range. Blood calcium is therefore not a reliable indicator of deficiency. We also need to question the ranges used in blood tests, if your B12 is within the wide range used by the NHS yet you have many symptoms indicating a possible deficiency. Then this should be looked into further. I have concerns with both higher end and lower end B12 readings. High readings could suggest a lack ion uptake at a cellular level or simply reflect recent food intake. Methyl malonic acid might be a more useful indicator of B12 levels as it measures B12 that has actually been used by the body. Methylmalonic acid is a metabolite measured in urine.
Identifying sub-clinical deficiencies.
We are all aware of textbook deficiency symptoms like pellagra and scurvy. When nutritional education has advanced so much since the definition of deficiencies it is sad that we still rely on such acute illnesses to define deficiencies. Simply having low levels of specific nutrients is enough to impact your physical and mental health without being diagnosed as clinically deficient. We are talking about sub-clinical deficiencies. Those that impact on your function and cause symptoms but may not be flagged as an issue by many clinicians. Although vitamin C deficiency is clinically recognised as scurvy many of us may not be getting enough but we don’t have scurvy. Instead we catch frequent colds or have poor skin health. We still have a higher need for vitamin C, a sub clinical deficiency, but not a deficiency according to medical textbooks. This is what we refer to as functional medicine.
Should we use supplements?
I recommend exercising caution when choosing to use nutritional supplementation with yourself or with your child. Supplementing one mineral will often have an impact on another and so it is important to have programmes approved and monitored by a professional. The quality and potency of supplements is also something to be considered. I recommend using professional quality supplements to ensure potency and that it is free-from unnecessary fillers.