The risk of dementia increases with age, affecting some 5 per cent of people over the age of 65. Dementia is also much more common in women and is now their biggest killer, causing three times more deaths than breast cancer.
Symptoms associated with a gradual decline in brain function, such as loss of memory and difficulty concentrating, tend to be lumped together as ‘dementia’, but there are two main forms of the disease with very different causes: Alzheimer’s (the most common) and vascular dementia.
True Alzheimer’s disease is caused by plaques (of beta-amyloid) and tangles that develop in the brain. Spherical clumps that float among neurons, plaques prevent the transmission of messages from one nerve cell to another, while tangles choke neurons to death from the inside. Vascular dementia, on the other hand, results from a problem with blood supply to the brain.
Beyond the pancreas
It’s now been shown that it’s not just your pancreas that produces insulin; your brain has its own supply and needs insulin for the survival of its cells. A low level of insulin in the brain is linked to brain-cell degeneration, while good levels of insulin are essential for their survival and function.
After reviewing all the evidence showing a connection between Alzheimer’s and type 2 diabetes, two pathologists from Brown Medical School and Rhode Island Hospital demonstrated that insulin levels are reduced in the frontal cortex, hippocampus and hypothalamus, all areas of the brain affected by Alzheimer’s, whereas the cerebellum, which is not affected by Alzheimer’s, did not show the same low insulin levels.1
In healthy brains, beta-amyloid, a brain protein, has positive functions like fighting microbes, transporting cholesterol and protecting against oxidative stress. It only becomes a problem when it forms plaques.
According to the latest thinking, the reason beta-amyloid may start to form clumps and tangles could lie with insulin and how it functions in the brain.
Up until just a few years ago, it was thought that insulin simply regulated blood sugar, but it’s now understood to have a number of other functions as well. It regulates neurotransmitters and brain chemicals like acetylcholine, which are important for learning and memory. Insulin is vital for healthy neuron function, especially in those areas of the brain most affected by Alzheimer’s—the hippocampus and frontal lobes.
Insulin is also important for the growth of blood vessels that help supply the brain with oxygen and glucose, and for promoting plasticity, enabling the brain to constantly make new connections over a lifetime.
Yet other evidence is cropping up, showing connections between type 2 diabetes, where regulation of pancreatic insulin is affected, and Alzheimer’s. Research on rats with type 2 diabetes showed that the animals’ brain function deteriorated rapidly as the disease progressed.2 The high levels of insulin present in their bodies blocked the enzymes that break down amyloid, an abnormal protein, usually produced in bone marrow, which can then be deposited in any tissue or organ. The amyloid builds into toxic clumps (plaques), which disrupt neurological function.
Other studies show that, in diabetic animals, Alzheimer-like changes in the brain arise in tandem with increases in beta-amyloid plaque.3 This suggests that, like the body, the brain can become insulin-resistant, unable to respond to insulin properly—a situation seen in the brains of human corpses.
In one such study, researchers took brain cells from newly dead people, some of whom had been diagnosed with Alzheimer’s, and soaked them in insulin. Brain tissue from those without Alzheimer’s showed active insulin signalling in response (brain signalling is maintained for a number of hours after death), but in those with Alzheimer’s, there was no such activity, particularly in the hippocampus, the centre of learning and cognitive function.
The researchers, from the University of Pennsylvania, concluded that patients with Alzheimer’s suffer from insulin resistance in the brain.4
Research is also emerging that insulin resistance in the body is involved in “negative cross-talk” that can cause Alzheimer’s to progress and make its symptoms worse.5
But the reverse is also true: a review by researchers at the University of Kansas Medical Center concluded that treatment of type 2 diabetes with insulin sensitizers like metformin and pioglitazone, agents that lower blood sugar by increasing muscle, fat and liver responses to insulin, can improve brain function and also slow the rate of cognitive decline in Alzheimer’s patients.6
Nevertheless, the same researchers also reported that amylin, a peptide made in the pancreas, clumps together like beta-amyloid, causing pancreatic beta-cell damage (as in diabetes), and also aggregates in the brain in those with vascular dementia and Alzheimer’s.7
It’s already known that people with type 2 diabetes have an increased risk (about 50–65 per cent higher) of developing Alzheimer’s. This suggests it may be possible to both prevent and slow the progression of both diseases by using the same tools, as the causes behind both are effectively the same: too much sugar in the diet.
Besides problems of insulin regulation, it’s also thought that inflammation plays a key role in Alzheimer’s. Inflammation can change blood flow in the brain just as it affects the blood supply to the heart, and can also worsen the already inflamed beta-amyloid-affected brain areas and cause neurons to age, so speeding up the usual age-related decline in their numbers.
Being on this blood-sugar roller coaster also releases the stress hormone cortisol, eventually increasing inflammation which, in turn, will worsen brain and memory function.
Like melatonin, the hormone related to sleep, cortisol has a circadian rhythm. Levels are higher in the morning, revving us up to start the day, and are then reduced at night, while melatonin is higher at night and decreases by morning. But if cortisol levels stay high, then melatonin levels will remain low.
In fact, it’s been noted that people with Alzheimer’s exhibit an effect called ‘sundowning’, when their symptoms get worse towards the end of the day.8 Production of beta-amyloid also follows a circadian rhythm, increasing during the day and reducing when the person sleeps. Even animals deprived of sleep experience a 25 per cent increase in beta-amyloid.9
This suggests that the sleep/wake cycle may play a part in Alzheimer’s through a connection with melatonin and/or cortisol, as the latter hormone is definitely related to blood-sugar levels.
You don’t even have to have prediabetes or full-blown type 2 diabetes for these negative brain changes to take effect.
In one study, people were given either a high or low glycaemic-index (GI) diet (the higher the GI rating, the quicker the food converts to sugar in the body). Within just four weeks, those on the high GI diet had higher levels of insulin and significantly higher levels of beta-amyloid in their cerebrospinal fluid compared with those on the low GI diet.10
And just having higher levels of glucose from eating too much sugar-rich food is a significant risk factor for dementia even if you don’t have diabetes.11 The rapid effects of glucose on the brain show how important it is to eliminate—or, at the very least, drastically reduce—added sugars and refined carbohydrates (like white bread and white pasta) from your diet. Get your blood sugar in balance by reducing and eliminating hidden sugars from the foods you eat.
Pure, white and brain-deadly
Research from Stanford University has provided the first large-scale, population-based evidence that sugar has a direct, independent link to diabetes. For every 150 calories from sugar consumed above the recommended daily calorie intake, there was an 11-fold increase in the rate of type 2 diabetes compared with when the 150 extra calories came from non-sugar types of food or drink.1
The major pan-European study, the EPIC-Interact, has also confirmed that just one sugar-sweetened drink a day increases the risk of type 2 diabetes by 22 per cent. Another interesting finding of this study was that pure fruit juices or nectars have no effect on diabetes risk. However, if artificially sweetened drinks are substituted for sugar-sweetened ones, they also increase your diabetes risk.2
Another major study from France, which tracked more than 66,000 women over 14 years, found that the risk of developing type 2 diabetes was higher for women who drank either artificially sweetened or sugar-sweetened drinks.3
Indeed, the risk was actually higher with the artificially sweetened ones, and the risk skyrocketed the more they drank. Half a litre of artificially sweetened drinks increased the risk by 15 per cent, while 1.5 litres caused a 59 per cent higher risk. But once again, this study found no link between drinking 100 per cent fruit juices and the risk of diabetes.3
The 5-day sugar detox
To assist in cutting down your sugar intake, I’ve created a 5-day sugar detox diet to help wean you off your sugar addiction
If you find the idea of slowly eating less sugar difficult, you may prefer a more radical approach. In fact, some people find it easier to cut out all sugar by going on a sugar detox.
If you want to make a radical change to your health and wellbeing, this is a great way to kick-start your body’s healing. It involves eliminating all added sugars, artificial sweeteners, fruit and starches for five days. Look on this as a chance to rethink the way you eat; it’s also an opportunity to recalibrate your metabolism and to reprogramme your taste buds to appreciate a variety of flavours in your food rather than just sweetness.
If you stick with it, you will notice very distinct results in gaining control over your sugar addictions. Sleep will almost invariably improve, as will stress levels, as your blood sugar and hormone levels start to fall into balance. Your skin will look clearer and brighter, your face may well lose any puffiness and your eyes will become clearer.
Inside, your body will be heaving a deep sigh of relief as it’s finally able to reduce inflammation and allow hormones to revert to a better balance. But besides your body, your brain will also thank you.
Foods to eat
Green vegetables: green is really your favourite colour on this detox, so load your diet with all types of green veg: bok choy, cabbage, kale, broccoli, courgettes, marrow, lettuce, rocket, green peppers, mangetout, beans, seaweeds, peas, broad beans, sugar snap peas
White vegetables: cauliflower, garlic, onions, leeks, celery, asparagus, fennel
Purple vegetables: aubergine (eggplant), purple sprouted broccoli, red cabbage
Good-quality proteins: fish, organic eggs, seafood, nuts, seeds, beans, tofu
Seeds and nuts (all types): including nut butters (homemade or without added sugar) and nut milks (again, no added sugar or sweeteners)
Quinoa: although this cooks up like rice, it’s actually a seed, not a grain; it’s also a complete protein
Buckwheat: also a seed, the flour can be used too
Sprouted seeds and pulses
Miso (fermented soybean paste)
Coconut (fresh, oil, cream): use coconut oil for frying (as a fat that’s solid at room temperature, it won’t degrade at high temperatures)
Herbal teas (nettle, peppermint, etc.): no fruit teas
Herbs and spices
Olives and capers
Cider vinegar, olive oil, flaxseed oil (for salad dressings)
Foods to avoid
Starchy vegetables: carrots, parsnips, sweet potatoes and potatoes are higher in carbohydrates (natural sugars) than the non-starchy vegetables listed above
Dairy products: most contain lactose (milk sugar), and it’s better to eliminate all the various kinds of sugars
Fruit: if you must have some, then opt for berries, which have the least amounts of sugar, while tomatoes and mushrooms will add variety to savoury food.
The skinny on ‘natural’ sugars
Many alternatives to sugar called ‘natural’ are anything but. Here’s my verdict (thumbs up or down) on the good, the bad and the ugly among alternative sweeteners. Wherever possible, rely on the natural sweetness of foods themselves rather than on sugar or artificial sweeteners, using carrots, raisins, beetroot, dates, figs and bananas as natural sweeteners.
Sold as a highly refrined white powder, which no longer has the goodness and fibre of fruit. Won’t cause the release of insulin as sucrose and glucose do, but will go straight to your liver—just like alcohol—causing weight gain and fat around the middle. Interferes with the production of hormones related to hunger and satiety (feelings of fullness), and so increases appetite. Also gets converted into unhealthy fats like LDL (‘bad’) cholesterol and triglycerides.
Verdict: Fine if naturally contained within fruit, but not as a white powder added to food
A natural sweetener derived from the starch of the root bulb of the Mexican tequila plant. Essentially refined fructose, made by a process similar to converting corn starch into high-fructose corn syrup (HFCS), shown to be damaging to health. Expensive if produced in the traditional way (by slowly boiling the sap).
Verdict: Could be up to 90 per cent fructose, as there’s no way to distinguish between commercially and traditionally produced products
A simple sugar mostly made up of glucose and fructose (up to 40 per cent in some honeys) that’s quickly absorbed into the bloodstream. The ‘blended’ or ‘produce of more than one country’ varieties often heated to temperatures as high as 71° C (160° F), which destroys natural goodness. In winter, some beekeepers feed their bees white-sugar water or HFCS as a substitute for natural flower nectar.
Verdict: Nothing more than a simple sugar that affects blood glucose quickly. If you must use it, buy organic and use very sparingly
This strong-tasting by-product of the three-stage process to extract sugar from sugar cane/beethas the least amount of sugar and highest quantities of vitamins and minerals, including vitamin B6, potassium, magnesium and manganese. Half its sugar content is fructose and glucose in equal amounts, while the other half is sucrose.
Verdict: May contain high levels of pesticides and other chemicals used in sugar cultivation and processing
Sold as a white powder and considered natural as it occurs naturally in plants like sugar cane and corncobs, but needs a lot of refining. Low in calories, it doesn’t trigger insulin, so useful for diabetics. Reduces dental caries, but as a sugar alcohol (polyol), ferments in the gut, causing diarrhoea and bloating.
Verdict: Hard on the gut and too processed to be considered a natural product
A sugar alcohol usually made from corn syrup and naturally found in stone fruits like prunes and plums. Often used in foods for diabetics as it triggers little or no insulin. A highly processed product, requiring hydrogenation. Gut side-effects are similar to those of xylitol.
Verdict: Heavily processed with negative effects on the digestive system
Evaporated cane juice
This newish ingredient in many ‘natural’ products is actually a sugar syrup from partially refined sugar similar to ordinary sugar, unlike unrefined sugar-cane juice, which is extracted either manually or electrically by crushing sugar canes and drinking the liquid with lemon or ginger.
Verdict: Processed sugar by any other name, the US Food and Drug Administration (FDA) has warned of mislabelling with this product
Made from the sap of maple trees.
Contains 34 beneficial compounds with antioxidant and anti-inflammatory properties, significant amounts of zinc and manganese, and 15 times more calcium than honey. Usually recommended for IBS (irritable bowel syndrome) sufferers as it causes the least problems with digestion. Mostly sucrose, with very small amounts of fructose and glucose.
Verdict: A good natural sweetener for cakes and for drizzling over crumbles, but buy organic if possible
Barley malt syrup (extract)
An unrefined natural sweetener derived from sprouted, dried, cooked and reduced barley malt, and a good source of some minerals and vitamins with almost no fructose or sucrose.
Verdict: A good choice as a natural sweetener. Malty taste may not suit all recipes, but brilliant on flapjacks
Brown rice (malt) syrup
A natural sweetener containing maltotriose, maltose and glucose. Cheaper versions are made from cooked brown rice cultured with enzymes to turn starches into sugar, while others use sprouted grains that release enzymes which break the grain down into maltose and other sugars. Buy organic, as more likely to be made from sprouted grains.
Verdict: A healthy sweetener devoid of fructose. Changes the texture of baked foods, so use when a little crunch is good, but sparingly in crumbles, flapjacks or healthy granola
Derived from the leaves of a South American plant of the same name and used for centuries as a sweetener in South America. Approved in 2011 for use in the EU. Up to 300 times sweeter than table sugar (sucrose) but with a slightly bitter aftertaste, Avoid products not made with 100 per cent stevia, since some contain dextrose and flavourings. As not absorbed through the gut, it should be a boon for weight loss, but primes your body to expect a certain amount of calories for the sweetness, and so may increase appetite and cause weight gain.
Verdict: Use in moderation and only as pure stevia
Whole cane sugar
Unprocessed sugar cane contains vitamins A, B and C, calcium, chromium, zinc and magnesium plus antioxidant polyphenols. During sugar-cane processing, the molasses pressed out of the sugar keeps all nutrients intact, as not refined or subjected to high heat.
Verdict: A natural unrefined form of whole sugar that’s absorbed more slowly into your bloodstream, but may be difficult to obtain
Made from palmyra palm flowers tapped to release their juice, which is boiled to produce a syrup and then crystallized. A traditional Ayurvedic ingredient containing B vitamins (including B12), it scores low on the glycaemic index (40), so is suitable for diabetics.
Verdict: A good natural sweetener and sugar alternative for cooking as well as in drinks
Coconut (palm) sugar
Also known as coconut nectar or blossom syrup. Made from the sap of coconut flower buds and turned into a syrup or crystals after minimal heating. Rich in B vitamins, magnesium, calcium, potassium, zinc, 17 amino acids, short-chain fatty acids, polyphenols, and antioxidants plus inulin, this prebiotic helps feed beneficial bacteria. Mixed opinions on its sustainability and whether collecting the sap affects the production of coconuts.
Verdict: Reputed to taste like brown sugar and a useful substitute for white sugar, but buy organic
Made from the root of the yacon, or Peruvian ground apple, a member of the sunflower family. Tastes like a cross between an apple and a pear, with good amounts of vitamins and minerals plus a prebiotic (fructooligosaccharide, or FOS), which helps to feed good bacteria in the gut. Traditionally made (without chemicals) by evaporation, like maple syrup. Low GI makes it fine for diabetics.
Verdict: Use instead of liquid sweeteners like honey and also for baking, but buy organic.
May not be suitable for
people with IBS due to high FOS content