The real symptoms of allergy
Often you’ll be asked to do a home trial of an elimination diet, followed by reintroduction of the avoided foods one by one to see if any cause a reaction. This is the only reliable way of diagnosing food intolerances at present.’
So if it’s not an allergy, what’s wrong with you?
Real symptoms: An allergy to dairy can cause hives, chronic itching and projectile vomiting
ALLERGY SYMPTOMS: Hives, a red rash, lip/facial swelling, wheezing, chronic itching, projectile vomiting, diarrhoea and stomach cramps.
INTOLERANCE SYMPTOMS: diarrhoea, bloating.
COULD THE SYMPTOMS BE SOMETHING ELSE? The intolerance symptoms are similar to irritable bowel syndrome (IBS), a common gut disorder. Canadian researchers found IBS was the real problem in up to half of all diagnoses of dairy intolerance.
IBS has no known cause or cure, but symptoms can be eased in most cases by increasing the intake of soluble fibre (fruit, vegetables and wholegrains) and fluids.
Another possible cause is ‘ resistance’ starches, which are formed when you reheat carbohydrates such as potatoes or pasta, says Dr Venter. ‘The reheating process changes their composition, so they literally resist digestion in the small intestine.’
WHY YOU NEED A PROPER DIAGNOSIS: ‘Cutting out dairy makes it harder for children to get adequate amounts of protein and calcium,’ says Dr Venter. ‘You can get these nutrients from other foods, such as tinned salmon or sardines containing bones, or green leafy vegetables, but they’re often not child-friendly.’
Adults may increase their risk of osteoporosis, while low levels of calcium in the blood can result in muscle spasms.
ALLERGY SYMPTOMS: Hives, facial swelling, wheezing, chronic itching, vomiting, diarrhoea and stomach cramps.
INTOLERANCE SYMPTOMS: Aching joints, stomach ache, bloating, depression.
COULD THE SYMPTOMS BE SOMETHING ELSE? Much factory-baked bread contains additives such as soya, cakes are full of sugar and most bread contains yeast ? any of these can upset the digestive system, says Dr Venter. Opt for good-quality wholegrain breads from a local baker who can tell you exactly what’s in your loaf, or make your own.
WHY YOU NEED A PROPER DIAGNOSIS: ‘The main nutritional deficiency from cutting out wheat is the B vitamins, essential for energy production and a healthy nervous system,’ says Dr Venter. ‘Wheat is also a good source of iron – a deficiency can affect your concentration and make you more susceptible to infection.’
ALLERGY SYMPTOMS: Heart palpitations, a sensation of intense heat and crushing headaches – usually caused by a deficiency of the enzyme aldehyde dehydrogenase needed to metabolise alcohol (an estimated 50 per cent of Chinese, Japanese, and Koreans lack this enzyme).
INTOLERANCE SYMPTOMS: Facial flushing, sneezing and congestion.
COULD THE SYMPTOMS BE SOMETHING ELSE? Some people react to sulphites and salicylates in wine.
These are substances found naturally in grapes, but that are also added by wine makers to develop flavours. Symptoms of sulphite sensitivity include wheezing, rashes and nausea, whereas salicylates can cause symptoms similar to hay fever. Salicylates are also found in beers.
But you could also be reacting to the fish and dairy products often used for fining wines, a process that removes any insoluble material that may cause a wine to become, for instance, cloudy (these, along with sulphites, have to be flagged up on the wine’s label).
ALLERGY SYMPTOMS: Shock, tightened airways and loss of consciousness.
COULD THE SYMPTOMS BE SOMETHING ELSE? You might have just eaten fish that’s off (scromboid poisoning) – the British Nutrition Foundation says almost half of all food poisoning cases are caused by raw or out-of-date fish.
Dr Venter explains: ‘Scrombroid poisoning causes red flushing, hives and diarrhoea, as often seen in fish allergy – however, scrombroid poisoning does not cause anaphylaxis. There is no such thing as fish intolerance, as far as I know.
Sudden onset: King prawns pictured in sweet chilli sauce. Symptoms of seafood allergy include shock and loss of consciousness
‘Fish allergies tend to be severe, where people can react by merely inhaling fish, or touching a work surface where fish was prepared,’ she says. ‘Also, you can be allergic to freshly cooked tuna but not canned tuna, or cod but not salmon – it’s often a very precise allergy.’
WHY YOU NEED A PROPER DIAGNOSIS: Cutting all fish from your diet deprives you of a prime source of lowfat protein, not to mention the hearthealthy omega-3 oils in fatty fish such as mackerel or salmon (although there are plant sources of omega-3s).
How to maximise your endurance training
Even though we have clearly discovered a number of things about how to increase strength, the last decade has seen an even more impressive increase in our understanding of how we can increase endurance. The fact that endurance training increases the number of mitochondria and fat burning enzymes in our cells has been known for over 40 years. But, in the last decade we have identified the genes that cause the increase and we are learning more every day about how to use nutrition and exercise to effectively turn these genes on and maximise our endurance.
In 2003, Dr Ron Evans and his colleagues showed that mice with an active form of the transcription factor PPAR∂ had more enzymes to breakdown fat and to power their muscles.
As a result, they could run for longer on a treadmill.
In a follow-up study, the Evans group gave mice a drug that activates PPAR∂ and showed that increasing PPAR∂ activity during training doubles the increase in endurance compared with training alone. Most of this increase in endurance was due to an increase in enzymes that break down fat.
PPAR∂ is normally activated by fat but just eating more fat is not the best way to increase endurance.
What we need to do to increase PPAR∂ (and get more endurance) is to use more fat when we are exercising.
One way to increase how much fat we burn in our muscles during exercise is to exercise in a glycogen-depleted state. When we exercise with low muscle glycogen stores, we increase the amount of fat we use as a fuel and this results in an increase in our fat burning enzymes and endurance. Therefore, if endurance is important for your performance, adding in a few sessions in a glycogen depleted state will really give this a boost.
In 2002, Dr Bruce Spiegelman and his colleagues showed that if there is more active PGC-1α in our muscles we get more mitochondria and endurance. We showed at the start of the decade that after endurance exercise there was an increase in PGC-1α and this was important for the training effect.
AMPK is an enzyme that measures the energy status in our cells. When lots of energy is being consumed (such as when we exercise) or when not enough energy is being produced (such as when we fast) AMPK is activated. When active, AMPK turns on processes that increase energy production (fat burning, glucose uptake, etc) and decrease energy use (protein synthesis, etc).
One of the things turned on by AMPK, either directly or indirectly, is PGC-1α. This may be how exercise increases our endurance. Therefore, activating AMPK and PGC-1α should be the goal of endurance athletes.
For endurance athletes and coaches, this translates into three practical points:
1. Train at a high intensity since higher intensity exercise increases AMPK more than low intensity exercise;
2. Do not use carbohydrate supplements when training since CHO supplements may decrease AMPK activation in response to exercise;
Consider adding one of the natural activators of AMPK to your training to maximise AMPK activation. Resveratrol (an extract from red wine) activates AMPK as does Berberine (an extract of the goldenseal plant).