Why don’t diabetes tests check my blood sugar levels?
Q I have type 2 diabetes and every time I go for my annual check-up I have loads of blood tests. I wasn’t sure what they were all for, so asked for a copy of my results and saw things including HbA1c and eGFR, which I’d never heard of, but no blood sugar levels. Can you explain? A
The raised blood sugar levels that occur in diabetes can not only cause symptoms such as tiredness, feeling thirsty and needing to pass urine more frequently, but can also increase your risk of heart and kidney problems and damage to your vision.
The higher your average blood sugar, the greater the risk of other complications. A check for your level of blood sugar only gives an indication of what it is at that particular moment and can be influenced by just having a glass of orange juice or a biscuit half an hour beforehand.
A blood sugar level result can be useful if it is thought to be very low or high, but it does not give a reading of the average level from day to day and that is what is important.
Glucose molecules in the blood normally stick to the haemoglobin molecules in red blood cells to form glycosylated haemoglobin, or HbA1c, and the level of this rises in direct proportion to blood sugar levels.
The glucose remains attached to the haemoglobin for the life of the red blood cell, so checking the HbA1c level can give an average of the blood glucose level for the past two to three months, giving a good indication of how well your diabetes is controlled.
A normal level is below 42mmol/l, and if you have diabetes you should aim to keep it as near to 48mmol/l as possible. A higher level indicates your medication and diet need adjusting.
Your kidneys filter blood to remove waste, including the chemical creatinine, and excess water to make urine. The estimated glomerular filtration rate, or eGFR, measures how much blood is filtered every minute, by measuring creatinine levels and can give a good indication of your kidney function.
The lower the level, the worse the kidney function.
A level of 90 or higher means your kidneys are working normally, a level of 60 to 89 may mean early kidney disease, while a level below 59 may mean kidney disease.
Q
My 16-year-old daughter has become very worried about the future of the planet and will only eat a plant-based diet. I work full time, so preparing different food for her has become a chore and so I’ve been relying on ready meals. I’m concerned that she is not getting all the nutrients she needs. Are vegan foods really healthier than others?
A The main health issue with a vegan diet is ensuring an adequate intake of iron and vitamin B12, which are mainly found in red meat, and required for healthy red blood cells. Calcium, which is found mainly in dairy products, is required for strong bones and teeth. Women of any age who are having periods are at higher risk of anaemia from their monthly blood loss, but ensuring adequate intake of calcium is especially important in young women, who are building bones that need to last through their lifetime.
Good sources of iron for vegans include green leafy vegetables and pulses (which also contain calcium), wholemeal flour and breakfast cereals fortified with iron, while vitamin B12 can also be obtained from fortified breakfast cereals and soya drinks.
Calcium can also be found in fortified drinks and tofu, while white and brown bread has calcium added by law in the UK.
The iron and calcium found in plant foods is absorbed less well than that found in meat and dairy products, so large portions may be required for an adequate intake, and a blood test to check levels once a year, especially in children and young adults can be a sensible idea. It is difficult to get enough vitamin D even from an excellent, well-balanced diet, and though it is possible to top up levels from the action of sunlight on the skin in summer, everyone should take a daily supplement from now through to April.
Vegan ready-prepared foods are no different from those containing meat – some are healthy, while others are highly processed and high in fats, salt and other additives. They are also more expensive than home-cooked foods, so I suggest you batch-cook fresh meals every weekend, which can be stored in the fridge or freezer.
Your daughter should also help you out – she is old enough and the burden of her lifestyle choice should not rest with her busy mum. Your wellbeing is important too.
Q I’ve just been contacted by my GP surgery and offered not only the Covid and flu vaccines, but one against pneumonia as well. Is this necessary? Aren’t the flu and Covid vaccines protecting me against pneumonia? I’m concerned about having three vaccines all at the same time.
A Pneumonia is a chest infection of the lung tissues, which can cause severe illness, with a fever, cough and shortness of breath.
It can be triggered by a variety of different bugs, including both the Covid and flu viruses, and also pneumococcus bacteria.
Giving a vaccine that protects against one of these unfortunately does not provide protection against the others, which is why everyone over 50 is being offered both a flu and Covid booster this autumn.
Additionally, all babies are routinely given the pneumococcal vaccine at 12 weeks and one year of age, and a one-off booster jab is offered to everyone aged 65 or over, which is why you have also been invited to take this up.
The immune system can respond to lots of different vaccines being given at once and it is safe and effective to give Covid, flu and pneumonia jabs at the same time.
You might have a rather sore arm afterwards, but that should only last a day or so and is far better than being seriously unwell with difficulty in breathing.
● If you have a health question for Dr Leonard, email her in confidence at yourhealth@express.co.uk. Dr Leonard regrets she cannot enter into personal correspondence or reply to everyone.