Are you tired, lacking in energy or suffering from aching muscles?
Most of us suffer these complaints on a regular basis, but can struggle to pinpoint why.
However rather than some grizzly disease, it could in fact be some of your most everyday habits or healthy eating regime that are to blame.
Here, Dr Sarah Brewer, a medical nutritionist, reveals how our seemingly mundane rituals - and popular medications - could be depleting your body of vital vitamins and minerals…
TEA AND COFFEE
Compounds found in these drinks, such as tannins in tea and chlorogenic acid in coffee, bind to various minerals in food and supplements, reducing their absorption.
For example, coffee can reduce iron absorption by up to 80 per cent if drunk within an hour of a meal.
These beverages also reduce the absorption of other minerals such as zinc, magnesium and calcium.
Any hot food or drink can also destroy the bacteria in probiotic supplements or drinks.
SOLUTION: In general, drink water with meals and wash down supplements (and drugs) with water or orange juice, unless otherwise instructed.
Wait an hour before and after taking a vitamin or probiotic supplement before drinking a hot drink/eating hot food so as not to kill the bacteria.
Bran and phytates (compounds found in wholegrains, legumes, nuts, seeds and unleavened bread) bind to minerals in the gut so they remain unabsorbed.
This can reduce your uptake of non-haem iron - that found in vegetables, cereals, beans and pulses, rather than red meat - by as much as 65 percent.
It can also reduce your absorption of zinc, calcium and manganese.
This problem does not occur with leavened (yeast-raised) bread, as yeast enzymes break down phytates so mineral-binding does not occur.
SOLUTION: If you are following a high-fiber diet, ensure you obtain enough calcium, e.g. from milk and dairy products, broccoli, nuts, seeds and pulses.
A pint of milk, for example, provides almost all your daily calcium needs.
Vitamin C (e.g. from orange juice) can boost non-haem iron absorption.
Several studies, including a report from the World Health Organisation, have raised concerns about how oral contraceptive pills can lower a woman's levels of folic acid, vitamins B2, B6, B12, vitamin C and E plus magnesium, selenium and zinc.
Why the Pill affects blood levels of vitamins and minerals is not fully understood, but may partly be due to fluid retention.
The estrogen and progestogens used in the Pill are steroid hormones which have effects on the kidneys and the way salt and fluid balance is regulated.
They tend to cause sodium and fluid retention, which can dilute the concentration of micronutrients in the blood.
There are also concerns that the Pill may reduce absorption of vitamins such as folic acid and increase their excretion through the kidneys.
This may lead to nutritional deficiencies – especially of folate/folic acid, lack of which increases the risk of foetal abnormalities (a concern if pregnancy occurs while taking the Pill or soon after stopping it).
Lower vitamin B2 levels may explain the headaches that some women experience with the Pill.
SOLUTION: It's important to follow a healthy, nutrient-rich diet that includes plenty of fruit and vegetables.
Aim for at least five portions a day, including dark green leaves (kale, spinach, spring greens, etc) for folate. Nuts, seeds and wholegrains are good sources of vitamins and minerals, too.
If you are planning a pregnancy at some stage in the future, a multivitamin and mineral is a good idea.
These speed up the movement of food through the digestive tract so there is less time for nutrients to be absorbed.
Excessive use of laxatives can deplete levels of many vitamins and minerals and can also lead to dehydration.
SOLUTION: A healthy diet providing plant fibres and sufficient fluids will help to avoid the need for laxatives.
Concentrate especially on dietary sources of magnesium (wholegrains, nuts, seeds, beans, dark leaves, seafood, dark chocolate!) as lack of magnesium is a common cause of sluggish digestion.
Don't take laxatives regularly – especially those that have a fast response such as senna. Opt for more gentle versions such as fibre-based laxatives.
Alternatively, take a probiotic to improve your gut health and digestion to avoid the need for laxatives in the first place.
Antibiotics (especially those similar to penicillins whose names tend to begin with 'cef', e.g. cefalexin, which are sometimes used to treat infections such as pelvic inflammatory disease, sinusitis, cellulitis and urinary infections) can interfere with the absorption of vitamin K.
They also kill probiotic bacteria in the large intestine that produce vitamin K so that levels needed for healthy blood clotting, and healthy bones, are reduced.
Tetracycline antibiotics (e.g. doxycycline used to treat acne, urinary infections, chlamydia) also bind to calcium found in dairy products.
This can decrease the absorption of both the antibiotic and calcium, meaning the drug is less likely to be effective. You're also at risk of calcium deficiency if using antibiotics long-term, e.g. to treat acne.
The main problem with broad-spectrum antibiotics such as these however, is that they can wipe out 'good' bacteria as well as the bad.
This can lead to well-known side effects such as diarrhea and Candida yeast infections (thrush), as well as contributing to symptoms associated with irritable bowel syndrome, such as bloating and constipation.
New research suggests that, by changing the balance of bacteria in the gut, antibiotics also increase the risk of anxiety and depression.
Just a single course increased the risk of depression by around 25 percent, according to a study in the Journal of Clinical Psychiatry.
SOLUTION: If you are taking long-term antibiotics (e.g. for acne) you will benefit from increasing your intake of several micronutrients.
Good sources of vitamin K are cauliflower, broccoli, dark green leafy vegetables and fermented foods such as soybean natto.
Calcium is found in dairy products, eggs, broccoli, nuts seeds and pulses. To increase your intake of magnesium, select wholegrains, nuts, seeds, beans – and dark chocolate. Leave an hour each side of talking antibiotics before consuming dairy products.
For those on long-term antibiotics, however, a multivitamin and mineral supplement is a good idea, along with a daily probiotic supplement to replenish your gut's digestive bacteria.
It's also important to ensure good intakes of vitamin D for general immunity. Enjoy 10 minutes sun exposure without sunscreen on sunny day days. Food sources of vitamin D include oily fish, liver, eggs or fortified foods.