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 (think alcohol, caffeine, medication, etc) in our lifestyles and environments. For example, 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. As nutritional therapists we have an eye for this detail and use it to inform our personalised recommendations.
Are blood tests for nutrient deficiencies 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.
Sub-clinical deficiencies are less obvious nutrient deficiencies. Where low levels of a nutrient are not causing obvious symptoms, but could be contributing to more pervasive symptoms like fatigue, low mood or a general feeling of not being well.
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. Sub-clinical deficiencies can impact on your function, well-being and cause symptoms but they may not be flagged as an issue by many doctors. For example, 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. We still have a need for more 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.
