Hot Nutrition Topics - Cholesterol and Diet

10 Questions about Cholesterol and Diet – Things you should know
Joyce N.Y. Mak, Accredited Practising Dietitian (Australia)

1.    What is Cholesterol?
Cholesterol is a type of fat that exists naturally in the body.   Cholesterol is necessary for different bodily functions such as forming cell walls, production of vitamin D, hormones and bile. The majority (70-80%) of the cholesterol is produced by our liver and a smaller amount (10-20%) is obtained from our diet. Healthy individuals are able to adjust cholesterol levels in the body.

2.    I have been diagnosed with ‘dyslipidaemia’, what does that mean?
‘Dyslipidaemia’ simply means the abnormal levels of lipids (fats) in the bloodstream. This may include high levels of total cholesterol, “bad” cholesterol and/ or triglycerides in the blood, and/or low level of “good” cholesterol (see table below). Any of these conditions increases your risk of developing cardiovascular diseases, including coronary heart disease and stroke. This happens through a process called atherosclerosis, where cholesterol builds up inside blood vessels, leading to the obstruction of blood flow. An imbalanced diet, lack of physical activity, overweight, having a family history of dyslipidaemia etc, can increase the risk of dyslipidemia and cause lipid levels in our bloodstream to become abnormal.

Whether or not you have dyslipidaemia, your aim should be to maintain various blood lipid levels to the following desired levels:

 

Desired levels

Total cholesterol

< 5.2 mmol/L

HDL-cholesterol (‘Good’ cholesterol)

> 1.5 mmol/L

LDL-cholesterol (‘Bad’ cholesterol)

< 3.4 mmol/L

Triglycerides

< 1.7 mmol/L

American Heart Association (Mar 2011)

3.    I avoid high cholesterol foods likes shellfish and eggs, why is my cholesterol still high? What can I do to lower my blood cholesterol levels? 
It is becoming clearer that ‘bad’ fats (saturated and transfats) have a much more important role to play in the development of heart diseases through augmenting blood cholesterol levels, and their intake should be controlled in our diet.  

‘Good’ fats (monounsaturated and polyunsaturated fats), on the other hand, can lower blood cholesterol and reduce the risk of heart disease. The biggest influence on blood cholesterol level is the mix of fats in the diet. The key is to substitute good fats for bad fats.

4. Which foods contain the ‘good’ and ‘bad’ fats? 
 

 

 

Sources

Diet Tips

‘BAD’ fats – Limit these in your diet

Saturated fat

 

Mainly comes from animal sources, full-fat dairy and a few vegetable sources.

 

-          Cut fat off meat and remove skin of chicken before cooking

-          Avoid high-fat processed meats e.g. luncheon meat and sausages

-          Use low-fat or skimmed dairy products

-          Avoid palm oil, coconut and its by-products, which are high in saturated fats

Trans fat

Main sources from fried foods, pastries and baked products that uses hydrogenated oil or hard margarine

-          Avoid fried foods

-          Avoid hard margarine, pastries, cookies, biscuits and other baked products that uses ‘vegetable shortening’

-          Look on the nutritional label and choose products with the least amount of trans fat.

‘GOOD’ Fats – choose to replace ‘Bad’ fats in your diet

Mono- & polyunsaturated fats

Contained in most vegetable oils; nuts and seeds and deep water fish

 

-          Choose healthier oils in your daily cooking e.g. safflower, peanut, canola and olive oil

-          Eat moderate amounts of nuts and seeds e.g. almond, walnut, pumpkin seed, flaxseed etc.

-          Oil, nuts and seeds are nevertheless high fat foods and should be consumed in moderation.

-          Eat fish twice or more every week

The total amount of fat intake should be limited, whether or not the type of fat is ‘good’ or ‘bad’.

5.    So, I have looked out on ‘good’ and ‘bad’ fats in my diet, do I still need to watch out for cholesterol in my diet?
Dietary cholesterols mainly come from meats, including seafoods and eggs. As long as you control the meat intake, you will not consume excessive cholesterol in your diet. You are suggested to consume 5-8 taels of meat daily.

6.    How many eggs can I have a day?
Since dietary cholesterols play a minor role in the development of heart disease, there is no restriction of eggs intake. However, you are suggested to control your daily meat intake to 5-8 taels per day and to consume a variety of meats in order to have a balanced diet. 

7.    What other aspects of my diet do I need to note if I have high cholesterol?
Having adequate amounts of dietary fibre, especially soluble fibre, in your diet may help the body rid of excess cholesterol in the body, thus lowering blood cholesterol levels. A daily intake of 2 serves of fruits and 3 serves of vegetables is recommended. In addition, choose more whole grain foods such as brown bread, brown rice and oatmeal to boost fibre intake. High blood cholesterol is often associated with high blood pressure, a diet that is low in salt could help to keep blood pressure under control.

The ultimate dietary goal is to eat an overall balanced diet by following the food pyramid. 

8.    Are there any other things I could do to lower cholesterol in addition to changing my diet?

Adequate physical activity, including aerobic exercise and muscle training, can also help to raise ‘good’ cholesterol (HDL cholesterol) and lower ‘bad’ cholesterol (LDL cholesterol) levels in your blood, so having an active lifestyle is important. Adults should aim to get at least 30 minutes of moderately to vigorous physical activity on most days of the week.

Moreover, maintain a desirable weight is also important in cholesterol control. Asians should aim to maintain a Body Mass Index (BMI) between 18.5 and 22.9 (BMI = (weight in kg)/(height in meters) 2.

9.    Do I still need to watch my diet even when I’m taking cholesterol-lowering medications?
Medication plus lifestyle modification (through diet and physical activity), as opposed to medication alone, can better prevent heart disease.   Remember to keep taking Cholesterol-lowering medications as instructed by your doctor even if you have great improvements in your diet and physical activity. Tell your doctor about your efforts to see if your medications should be adjusted.

10.  Where can I seek more advice on having a heart-healthy diet?
A registered dietitian can provide you personalized dietary advices that suit your lifestyle and health status. Look for a registered dietitian from the HKDA website.


References:
American Heart Association. www.heart.org (accessed March 2011)
Central Health Education Unit, Department of Health, Hong Kong. Health Zone. http://www.cheu.gov.hk/eng/index.asp (accessed March 2011)