KEY POINTS:
Lemons and limes
Come winter and a runny nose, and everybody starts quaffing hot lemon drinks. What is it about lemons and their reputation as a health booster?
Lemons were originally bred as a cross between limes and citrons. They have their roots in Southeast Asia, from where Arab traders brought them back to Egypt and Africa around the 10th century, and from there to Europe and the New World.
A major reason why lemons and limes are so sought after is that they're one of nature's richest sources of vitamin C - they contain 61g per quarter cup. Our bodies need vitamin C to produce collagen, which forms the connective tissue that holds our skin, ligaments, tendons, bones and other parts of the body together. Vitamin C is also an important antioxidant, protecting our cells, blood vessels and membranes against harmful free radicals, which are caused by pollution, sunlight and our own bodies, as they naturally shed toxins. Vitamin C keeps our arteries plaque-free, our hearts healthy and our immune systems strong and robust.
Vitamin C can also relieve osteoarthritis and rheumatoid arthritis, where inflamed joints are an issue.
Research shows that compounds in lemons and limes called limonoids help fight cancers of the mouth, skin, lung, breast, stomach and colon. Particularly interesting is a substance in limes called flavonol glycoside - not only can it stop cancer cells in their tracks, it also appears to be a very strong natural antibiotic.
When you're out "lemon hunting', choose thin-skinned, bright yellow, heavy fruit - they're juicier than thick-skinned ones. Lemons will stay fresh at room temperature for roughly a week and in the fridge for up to four weeks - or freeze as ice cubes for later use.
The peels of limes and lemons contain natural substances called oxalates, which can cause health niggles in people who have kidney or gallbladder problems. And beware of waxed peels - you never know what chemical is in them, so organic is best, even if the fruit looks a little rough around the edges.
Onions
Onions may make us cry like a baby, but there's a lot to laugh about when we think about what they can do for our hearts, stomachs, bones and numerous other parts of our bodies. Besides, they're by far the most popular flavouring vegetable in the world.
Onions are rich in powerful sulfur compounds. This is what gives them their pungent smell and many of their incredible health effects. One such sulfur compound (allyl propyl disulfide) is responsible for lowering blood-sugar levels and for increasing our resistance to insulin, one reason for diabetes sufferers to eat onions.
Another onion ingredient that helps control blood-sugar levels is chromium. This important trace mineral - in conjunction with onion's sulfur compounds and vitamin B6 content - also has the power to lower bad cholesterol and keep our blood pressure in check. As a result, our arteries stay unclogged and plaque-free, reducing our risk of heart disease, heart attacks and strokes. The goodness of onions doesn't stop there - they also protect us against many forms of cancer, including ovarian, breast and prostate cancer. Eating onions once or twice a week can also significantly lower our chances of developing colon cancer, as onions contain flavonoids, and one of these in particular - the antioxidant quercitin - has been found to stop tumour growth and to protect colon cells from being damaged by cancer-causing substances.
There are at least two more reasons why eating onions regularly helps keep the doctor away. For one, onions keep the cells that break down bone from being active, which means stronger bones and less chance of developing osteoporosis for menopausal women.
They also contain anti-inflammatory compounds, such as vitamin C and quercitin, which can relieve the symptoms of rheumatoid arthritis and asthma.
Onions are also good bacteria killers, which makes them great for fighting colds and influenza.
Onions come in many varieties, shapes, colours, flavours and degrees of sharpness.
Generally, the most pungent onions deliver many times the health benefits of their milder cousins - that's your yellow onions (the brown-skinned, white fleshed type that is available all year), pickling onions (baby yellow onions), the round types of red onions and shallots, the small, copper-coloured onion popular in French and Asian cooking.
When buying onions, choose ones that are clean, closed at the neck and that have crisp, dry outer skins. Avoid those that are sprouting or mouldy. Store them in a cool, well-aired area away from bright light and not wrapped in plastic.
And in case you wondered why onions bring tears to our eyes - it's the phytonutrient allyl sulfate that is produced when onion's sulfur compounds come in contact with air as you peel them.
There are three tricks to prevent you from bawling your eyes out:
1) Peel and chop onions as fast as you can.
2) Soak them in water for a while.
3) Wear goggles or contact lenses while chopping _ this works every time.
Brussels sprouts
My other half's take on Brussels sprouts is that something you have to cut a cross into to let the devil out can't be good for you. Truth is, whether you hate 'em or love 'em, these mini-cabbages - named after the Belgian region near Brussels where they first grew - are one of nature's greatest gifts to mankind.
Brussels sprouts are highly effective in protecting us against cancer. This is because they are full of antioxidant sulfur-containing organic compounds called glucosinolates.
One glucosinolate derivative of note is sulforaphane. It causes the liver to produce enzymes that kill cancer-causing chemicals, and one study suggests that it can stop cancer cells from growing.
Sulforaphane could also be good for our colons. Studies show it can:
Cut the development of pre-cancerous colon cells in half by forcing diseased cells to commit suicide;
Offer special protection to people with cancer-prone genes.
To be fair, the fibre in Brussels sprouts does its bit to keep our colons cancer free, too.
It promotes a smooth digestion, which means that no harmful matter in the food we eat stays in contact with the colon lining long enough to harm it. And don't be worried that you'll have to eat cargo loads of Brussels sprouts to reap their anti-cancer benefits; three to five cups a week is all you need. They're best eaten steamed - if you boil them, you will destroy all their cancer-fighting agents.
Brussels sprouts are also an excellent source of vitamin C.
If you are pregnant and don't fancy Brussels sprouts, learn to love them. They're one of the richest sources of folic acid, a B-vitamin that's essential for dividing the DNA in a foetus' nervous system properly.
The only people who should avoid Brussels sprouts are those with thyroid problems. Sprouts contain goitrogens, which can interfere with how well this gland works.
Brussel sprouts are available from supermarkets and vege shops all year and are at their best from autumn to spring, when they're in peak season.
- Extra, HoS
