Good fats, bad fats,
Dr Richard Beyer
ATS, oils, salt and cholesterol are all factors that have a significant bearing on our health, particularly in middle to later life. How often do we hear of an untimely death of a close friend or relative from some sort of heart-related incident. A closer look at the factors in our diets may help us make informed and perhaps healthy choices.
Firstly, fats and oils (often called lipids) are nature’s way of storing energy efficiently. In a given weight they store almost twice as much energy as carbohydrates.
They are what is known as energy dense. Fats and oils are very similar in their chemical make-up but we know that oils are generally liquid at room temperature and fats are solid.
In ghee you may see butter fat and oil in the same bottle with the oil at the top and the fat as the cloudy bit at the bottom and coconut may also have both oil and fat in the same bottle. Fats vary according to their source.
Oil from soybean is different from lard or butter. The difference comes from the chemistry. Part of the fat is made up of a number of fatty acids. These are nothing like the acids that you find at home such as citric acid in limes or acetic acid in vinegar but are long chains too small to see.
The make up of these acids decides the nature of the fat or oil. Some are known as ‘saturated fats,’ which has nothing to do with wetness but refers to the chemical make up.
These are generally found in fats such as mutton fat or canned meats. The acids in these foods are strait chains and fit together like stacked spoons. This is what makes them very hard at room temperature or straight from the fridge.
The saturated acids are so tightly stacked, they will not allow water to mix in with them. As normal fats float as droplets or fatty surface when they are in soup or peanut butter and so they are considered to be low density fats (lipids) or LDLs. Often called bad fats.
Other types of fatty acids are unsaturated and are kinked or bent so they cannot fit together so this is what gives them a different melting point and are still liquid even in the ‘fridge.
Because the unsaturated fats are kinked and have a random structure they allow water to get in between them.
Water is denser than fat so these unsaturated fats mixed with water have a higher density are therefore high density fats (lipids) or HDLs. Often called good fats.
In fact no fats are good if too many are included in the diet. Our energy usage is like a bank account. If we take in more energy than we use in daily chores or sport then it gets stored.
The storage of energy in our body forms the layers of fat in the arms, hips, tummies and thighs. If diets have high levels of calories from fat that is not burned off during exercise we put on weight and eventually become obese – not good for the heart.
What part does cholesterol play? Cholesterol is a waxy substance found in everyone’s blood. Your body needs cholesterol to build healthy cells, but high levels of cholesterol can increase your risk of heart disease.
In some cases high cholesterol comes fro-m the diet but in some cases high cholesterol is a family trait. In any event it is wise to avoid cholesterol in the diet. It is in high concentrations in dairy products and animal fats. What is more the cholesterol and bad fats increase in sheep-meat, beef and goats as they get older.
Fatty acids change their links as we digest them and will stick to cholesterol. When the saturated fats (LDLs) stick to cholesterol this has a tendency to stick to the inside of blood vessels.
White blood cells attempt to digest the fats and the combination of white blood cells, cholesterol and LDL will form sticky deposits known as plaques, Over a long period of eating saturated fats these plaques build up and restrict blood flow to vital organs such as the heart and the brain.
Because the unsaturated fatty acids from oils are kinked they do not form these dangerous plaques as readily. Hence you hear your doctor or your dietitian or nutritionist telling you to stay off saturated fatty diets.
And if you are a regular to this column will know that the label will give you that information.
Salt
An adult body only needs around 1 to 2g of salt (460 to 920mg sodium) per day to function. Sodium intake above 2,000mg per day is associated with high blood pressure, which is a risk factor for kidney disease and cardiovascular disease.
A major issue is that salt boosts other flavour so our desire tends to increase unless over time. Crisps and puffed products increase the trend towards salty food.
Bread is also a significant source of salt (a slice contains about 100 to 200mg of sodium) and therefore a problem because bread is such an important part of the diet.
To make matters worse bread is usually eaten with butter which also often contain high levels of salt. What may appear as a healthy lunch-time sandwich may in fact give you not only saturated fat but also a significant dose of salt.
Importantly, this column is not designed to diets dull, miserable or boring. Labels will tell you a lot about what you are eating and help you make healthy choice.
Fiji has great natural fruits, vegetables and fish there are so many great chefs, housekeepers and amateur cooks that create great exciting healthy food choices. Enjoy your lovo, your Sunday roast or your curry but leave the salt shaker on the shelf not on the table and try to increase the veggies and fish.
RICHARD BEYER is an English-born food scientist having worked in food industries, academic research and government throughout Australia, New Zealand, India and Europe. Since 1996 he has settled in Fiji and spent time at USP teaching and researching.
In 2006 he was appointed permanent ssecretary to the then Department of Agriculture. Since leaving this post in 2010 he has undertaken consulting around the region settling on his current focus — working with disadvantaged communities on smallscale food processing. The views expressed in this article belong to the authors and do not necessarily reflects the views of this newspaper.