Tuesday, April 14, 2009

Eat your way to lower cholesterol


WHILE some foods are directly linked to raised levels of cholesterol, other foods can actively lower it. CATHERINE COLLINS writes.

CHOLESTEROL is often seen as a dietary bad guy - and fairly so. Too much of the wrong type sloshing around inside is a massive risk to our heart health.

As a dietician in a busy hospital, I see first-hand the devastating effects of raised cholesterol. A third of all deaths are caused by cardiovascular disease and it is a major risk factor for heart attack, stroke and other debilitating conditions such as angina.

Much of my job is trying to help patients lower their levels through diet and I know how confusing it all can be.

In February, the humble egg was finally exonerated after decades of being unfairly linked to raised cholesterol. Many authorities had recommended we consume no more than three eggs a week but scientists from the University of Surrey, in a review of existing data, found that eating them had an "insignificant" effect on cholesterol levels.

While eggs may be in the clear, many other foods do have a significant effect on blood cholesterol.

What isn't always known is that while some foods are directly linked with raised levels, other foods can actively lower blood cholesterol, and so reduce the risk of developing heart disease.

What is cholesterol?

Generally, it's not something we consume, like a vitamin or mineral - most of the cholesterol in our blood is made by the liver.

Why, you may ask, would the body manufacture something so bad for us? Cholesterol is essential for life - it is integral to the body's process of using fats in our diet , which are vital for the manufacture of body cells, bile salts, hormones and vitamin D.

So why is it a problem?

Fats cannot dissolve in our watery blood. Instead, the liver packages them into cholesterol-rich fat balls with an outer protein layer known as lipoproteins.

There are two key lipoproteins found in the blood: LDL (low-density lipoprotein) "bad" cholesterol, and HDL (high-density lipoprotein) "good" cholesterol.

Remember, it is the ratio of LDL to HDL that is crucial in determining our heart-disease risk.

We want our LDL to be low and our HDL to be high - and the good news is that both are influenced by what we eat.

Why HDL is the hero?

LDL is the main fat and cholesterol carrier in the blood, delivering to the liver and other cells.

The body requires only a relatively small amount of fat for a healthy metabolism but with high-fat diets or those high in saturated fats, LDL levels in the blood become raised.

LDL can shed its load of fat and cholesterol into our artery walls, forming plaques that narrow the artery, causing long-term damage to our circulation and heart. The more LDL we have, the more likely this is to happen.

In contrast, tiny HDL lipoproteins have a fantastic cardio-protective effect - they can actually reverse the damage caused by LDL activity by pulling fatty deposits from the arteries and returning them safely to the liver.

Diet and LDL

The more fat we eat, the more LDL we make and the longer it takes to clear from the blood - so a healthy diet is never a high-fat one.

The type of fat we eat influences LDL levels. A diet rich in saturated fats (found in pastries, fatty meats, full fat cheeses, and many snack foods) increases "bad" LDL levels, by reducing the ability of our body cells to take up its contents.

Trans fats, made when liquid oils are "hardened" into more solid fats used in fried and baked goods, are the most damaging fats we can eat.

Our body cannot use trans fats so, once absorbed, they're carried round in the LDL until they are dumped, unused, into the artery walls.

Oats, pulses and some fruits are rich in soluble fibres that lower LDL levels by binding to bile salts in the digestive tract, preventing their recycling. The liver will use LDL cholesterol to make replacement bile salts, so lowering LDL levels in the blood.

Oily fish such as mackerel, fresh tuna, sardines and salmon are rich in omega-3 fats that improve blood lipoprotein levels that can also stabilise heart rhythms.

Boosting your fruit and vegetable intake to at least five portions a day provides a range of plant substances that stabilise LDL and improves artery health, both reducing the risk of artery damage.

Eating more of these low-calorie foods also helps us to lose weight, another factor that can significantly lower LDL levels.

Cholesterol products

Plant stanol and sterol esters, found in fortified foods and Benecol, Flora Pro-Active and Danacol, have a similar, more powerful effect and have shown to reduce LDL by 15 per cent - which is a significant reduction in terms of heart health.

Keep healthy for longer with diet -friendly foods

* Although not understood entirely, once atheroma (thickening of the walls of an artery by deposits of cholesterol) has been established, it can partially regress if a healthier diet is adopted or exercise levels are increased as long-term measures.

* Monounsaturated fats (such as olive and rapeseed oils) also lower LDL levels and boost HDL levels, while polyunsaturates (from corn or sunflower oils) lower LDL levels.

* A small amount of alcohol - one unit - most days and half an hour of aerobic exercise daily, such as brisk walking or cycling, both independently boost HDL levels.

* Simple dietary and lifestyle changes can significantly change your cholesterol profile - within two to three months of improving your diet , taking more exercise and losing excess weight. - Daily Mail

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