Post-surgical nutritional deficiencies and testing

This is such a massive topic I am going to try to keep it brief.

Despite the modern pressure to go vegetarian or vegan, the brains of our ancesters would not have increased to the size and complexity that they are if we continued on the same diet as gorillas. We have evolved to be omnivores and there is evidence to suggest fat extracted from brains and marrow contributed to a nutrient rich diet. We are unlikely to get the digestive system of ruminants in the not too distant future. Even Tibetan monks in the Himalayans eat the occasional yak.

We have the acid containing stomach like carnivores to break down meat and protein; a pancreas and liver to break down carbs and fats, a long small bowel to absorb nutrients and a large bowel to absorb water and process fibre. If it all works, it is a finely tuned engine.  Clearly oesophageal cancer patients have this lovely dream-like scenario blown clean out of the water when they get diagnosed, leaving them with a whole host of new stuff to deal with. As we eat smaller meals, everything we eat has to count in terms of calories and nutrition. Unless you know what you are doing, this is not the time to stop eating meat. 

The evidence

It is not surprising that after oesophagectomy (partial gastrectomy), nutritional status can go into decline due to stomach reduction or removal altogether. A number of patients are not warned about deficiencies. Is this because some dieticians are in denial that deficiencies occur or are they only involved for such a short period of time, they never get chance to see the scale of the problem? Whatever the reason, some forward thinking dieticians in London have done two pieces of work and admit that they still do not know how best to address longer-term deficiencies in post-oesophagectomy patients.

This enlightening audit by Alice Kidd in 2014 is well worth a read. In addition in 2017, a team at Imperial College London published this paper on the same subject. They report that two thirds of oesophagectomy patients get deficiencies in ferritin, B12, vitamin D and zinc and recommend regular screening but they do not specify a frequency.

I feel very strongly about the empowerment of patients over their nutrition, so much so that I am going to stick my neck out here and say three things:-

(i) be proactive and get to know your blood results and what is normal for you, preferably before any treatment starts

(ii) do not rely on dieticians or specialist nurses to remember to test you or even think it is important – take it from me – it is important. They will only do it when clinical symptoms arise and by then you will be feeling unwell.

(iii) ask for tests regularly or get them done privately.

OK – let’s break this down.

Baseline blood tests

I have already recommended getting a baseline blood test in an earlier post on preparing for surgery.  Ideally get one done before chemotherapy starts. The key values as shown in the papers above are iron, ferritin, calcium, magnesium, vitamin D and vitamin B12. You could throw in a fasted cholesterol and also a HbA1c plus liver and kidney function and bone profile for good measure. 

Bloods are done prior to each chemo appointment so ask for the results, ask questions and keep an eye on any changes.  Any doctor or health professional who can look you in the eye and tell you, you might die from sepsis or on the operating table, should not have any problem sharing your blood results with you or what they mean. Most of the time, the lab will flag up any values that fall outside the ranges, whether it be low, high or just on the cusp. It is also worth noting that trends or obvious declines or increases are what to watch not the odd fluctuation. This is why a baseline is good as it shows what is normal for you to start with. The caveat for this is if the illness is already causing problems with swallowing and eating in general and levels of certain vitamins and minerals like iron have dropped.

What do the numbers look like?

Below is a table showing each parameter, units and range to give an overall feel for what you are looking at. It is worth noting that different hospital and indeed GP labs have slightly different ranges but we are only talking very small amounts. It is the lower and upper end of the scales you need to keep an eye on. I will provide links to valuable sources of information but there is so much pseudoscience on the internet – suffice it to say that if these are all in range – you can say that you are biochemically sound even if you feel a bit off kilter.

Parameter Value Range  Meaning Source
Vitamin D 64 nmol/L (50-200) Adequate NHS Labs
Vitamin B12 612 ng/L (180-910) Normal NHS Labs
Folate 8 ng/mL (>5.4) Normal NHS Labs
Iron 17 umol/L (5-33) Normal NHS Labs
Ferritin 189 ug/L (10*-291) Normal NHS Labs
Calcium 2.4 mmol/L (2.2-2.6) Normal NHS Labs
HbA1c 37 mmol/mol (<42) Normal NHS Labs

Going forward

I will endeavour to get my bloods done every 6-12 months. If you are in decent shape before surgery and can eat relatively well after or have a jej feeding tube, your nutritional status should be OK for the first few months. It may go into slight decline when you start on real food. This can be due to the reduced volume of food, insuffient enzymes to break macronutrients down or reduced acid due to reduced stomach capacity or acid reducing medication like omeprazole.

B12 needs something called intrinsic factor in the stomach to be absorbed from food – so without exception, all gastrectomy patients will need lifelong B12 injections and probably iron supplementation. Iron is problematic as the body does not absorb it too well anyway. Try to eat iron rich foods where possible alongside something with vitamin C to help absorption. Ferritin levels represent stored iron and if these remain optimal you should be OK. In the table above it says that over 10 is OK for ferritin but there is some anectdotal evidence to suggest that below 20 and your hair may start to suffer. It is also worth noting that one in 200 people have a gene for haemochromatosis which is the over storage of iron in the blood so it is a good idea to have iron levels checked as unnecessary oversupplementation can also be extremely harmful.

Partial gastrectomy patients as stated above have been shown to need regular B12 and iron. You could try eating a bowl of Ready Brek each day which is fortified with B12, iron and folate. I do not know if this is enough to keep deficiencies at bay but do not wait for their values to bottom out, as by then you will feel unwell and you already have enough to deal with.

Vitamin D is important for the uptake of calcium into the bones. Being in full sunshine for 20 minutes a day helps to make vitamin D in the skin or you can absorb it from food.

Private testing

If your health team or GP are not forthcoming on the testing, exercise your consumer rights and buy your own. Vitamin D testing can be done cheaply and simply via a prick test.

For general health tests, Micki Rose has a great service and is very knowledgable over a whole wealth of tests. I have used Micki’s site a few times to order tests.

There is a new service on the market called Thriva.co – I have tried using them but the amount of blood required is impossible for me to extract via a simple prick test. You may have better luck.

These are just ideas – the best people to do your tests are your GP or at the hospital at the time of a follow up.

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