Professor Murray Skeaff is head of the Nutrition Department at the University of Otago and a specialist in oils and fats. Skeaff has surprising news when it comes to our fat intake and blood cholesterol levels.
It is the type of fat in our diet, rather than the total fat contained in our diet, that largely effects our cholesterol levels and CHD risk. Both saturated fats and trans-fats increase our LDL or 'bad' cholesterol levels. Trans-fats also decrease our levels of HDL or 'good' cholesterol levels. So trans-fats are a doubly bad whammy and are unequivocally worse than saturated fats. But, that doesn't mean saturated fats are okay, it means we should limit both.
Polyunsaturated and monounsaturated fats have positive effects on our blood cholesterol levels, reducing the total cholesterol to HDL cholesterol ratio. This ratio is considered a far more accurate predictor of mortality from CHD than total cholesterol, according to a substantial 2007 review published in the prestigious journal Lancet.
Simply decreasing our total fat intake has very little effect on our cholesterol levels and CHD risk. What we need to do is remove saturated fat from our diet, in New Zealand this is largely dairy fat, and replace it with poly and monounsaturated fats. In practise this means some basic substitutions:
- Swap butter (over 50% saturated fat) for vegetable-oil based margarines (5-18% saturated fat) - most NZ margarines have just trace amounts of trans-fatty acids and considerably less saturated fat than butter, check the labels
- Swap full-fat dairy products (milk, cheese, icecream) for low-fat options - one month down the road and you won't even miss full-fat products
- Swap animal fats in cooking (like lard, chefade etc) for good cost-effective vegetable oils like canola, sunflower and soybean oils, these are even better at improving cholesterol levels than the more expensive olive oils!
- Swap high-animal fat products like french fries for a healthier option like baked potatoes
But, then is the fun part. You get to add other sources of good fats to your diet - like nuts and seeds. A small handful of these as an occasional snack is a great idea - toasted almonds are my personal favourites along with Brazil nuts. My biggest issue is trying to keep the handful small!
Jennifer Bowden graduated from Massey University as a nutritionist with both a Bachelor of Science with First Class Honours, majoring in Human Nutrition and a Master of Science with Distinction, majoring in Human Nutrition. Check out her website and blog, Thinking Nutrition, for more health topics and nutrition conversations.
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