Ok here goes, my attempt as a mum with a background in Human Nutrition to understand the current situation in regards to fats, oils and health (mainly heart disease risk).
Lets start with some facts that are not in question at all
- Heart Disease is the biggest killer in New Zealand
- Obesity and being overweight are a risk factor for heart disease
- Cholesterol is risk factor for heart disease
These facts are well researched and I think pretty non controversial
Obesity, overweight and the fat we eat
We become overweight because of a simple reason. We eat too much food. Well more specifically we consume too much energy in the form of food. If you eat more energy than your body burns off you will gain weight in the form of fat stores. Your body doesn’t care in what form that excess energy enters your mouth (fat, carb, protein, sugar, alcohol) if more energy enters your system than your body burns off it will be stored as fat.
So it is worth noting the energy content of food types.
Fat has the highest energy content per gram. But we can over eat on any type of food, and if we do it will be stored by our amazing body as fat for use later on. A great survival mechanism for when food is in short supply, but can become an issue in the world of plenty most of us from New Zealand are lucky to live in.
Cholesterol is a type of fat, its soft and yellowish and something that I believe if a toddler could get their hands on, they would have a field day with. It is in some of the food we eat (only animal products), and it is the nasty stuff that narrows and or blocks our arteries causing heart attacks. But that is not the whole story. Cholesterol is also made in our body and preforms some pretty important roles:
- It is part of our cells membranes, keeping them soft flexible and fluid.
- it is needed for our body to produce a number of hormones and Vitamin D
- It is one of the building blocks needed to create bile acids which we need for digestion.
A Human body without sufficient cholesterol is not a healthy happy human body.
When it comes to cholesterol it is now recognised that the majority of cholesterol circulating in our blood is not due to the cholesterol we eat. That is why we have seen changes/relaxations when it comes to the number of eggs people should be including in their diet on a regular basis. Yes, eggs yolks contain cholesterol but eating cholesterol doesn’t really raise our blood cholesterol levels. Our blood cholesterol levels are due to what goes on in our liver not what cholesterol we actually eat.
Our liver is a very industrious factory. One of it’s many jobs is to produce not only the cholesterol our body requires, but also the transport vehicles the cholesterol needs to get places.
Cholesterol is transported around our body by lipoproteins. In the heart disease story there are two types of lipoproteins that transport the cholesterol around our body. Both are made by the liver but the two types have completely different functions.
Low Density Lipoproteins (LDL)
From a heart disease perspective I always think ‘L’ for ‘Lousy’. LDLs are the toddlers of lipoproteins. They take the cholesterol out into our body and dump it all over the place. Sometimes in places where it should go to perform important roles, and sometimes to completely random places where it can come to no good (i.e. causing blockages in arteries etc) Just like a toddler with food, toys or anything else really, they put stuff in all sorts of weird and wonderful places.
If an artery has become blocked due to a cholesterol plaque (build up) it will be because LDLs have ‘left’ the cholesterol there.
High Density Lipoprotiens (HDL)
On the flip side are ‘H’ for Happy. HDLs do the reverse they cruise around our body a bit like a mum, collecting misplaced cholesterol and transporting it back to our liver to be processed and removed.
So when it comes to cholesterol and heart disease risk, we run into a problem when the ratios of cholesterol, toddlers (LDLs) and Mums (HDLs) get out of kilter.
Think of a household like mine:
One mum 3 mobile children: Chaos, Mess, Heart disease risk high!
Or alternatively my sister in law’s current situation:
One mum, one non-mobile baby: Peace, Tidy, Heart disease risk low!
How much cholesterol and what type of lipoproteins our liver makes is affected by a number of lifestyle factors. One of which is the types of fat that we eat. Not the cholesterol we eat but the type of fatty acids we eat.
When I was at university studying Human Nutrition I was taught the following
Saturated Fatty Acids (SAFAs)
Increase LDL and decrease HDL, i.e. More toddlers, more mess, less mums, less clean up crew
Monounsaturated Fatty Acids (MUFAs)
Decrease LDL and increase HDL, i.e. Less toddlers, less mess, more mums, more clean up crew
Polyunsaturated Fatty Acids (PUFAs)
Decrease LDL not much change to HDL, i.e. Less toddlers, less mess, about the same amount of mums and clean up crew.
So when I was studying the general consensus was reduce saturated fatty acids, increase unsaturated fatty acids (particularly monounsaturated fatty acids) and your heart disease risk will improve.
Currently there is some debate within the clinical research, and literature. Most of which centres around the results of a large meta analysis published in 2014. (Although there have been other papers and various opinions published since as well)
This is my synopsis of what has changed,is changing or might change
When I studied I learnt that all fatty acids within a class have the same or similar effect on our cholesterol and lipoprotiens. i.e. all SAFA are bad, all MUFA are good. The meta analysis has shown that this may not be the case.
If we take saturated fatty acids for example. It would seem that within this family not all of the fatty acids cause the same changes to our blood cholesterol profile. Some of the fatty acids in the group may increase our risk factor heavily, others only marginally (e.g. Palmitic & Stearic acids found in Palm oil & animal fats respectively) and some may actually have a protective affect (e.g. Margaric acid a dairy fat)
A similar picture was revealed when omega 3 and omega 6 polyunsaturated fats were reviewed. There was no significant associations between total PUFA intake and heart disease risk. However when specific omega 3 and omega 6 polyunsaturated fatty acids were singled out namely Docosahexanoic acid and Arachidonic acid (which may be familiar to you from my article on infant formula) a reduction in heart disease risk was seen.
This is one of the reasons why we have seen a sudden upsurge in the popularity of coconut oil and coconut products. The fact that there is now some evidence to show that all saturated fats may not be as bad as first thought has been used heavily in the promotion of Coconut Oil. There is more to the story when it comes to Coconut Oil though. I will be going into it in more detail in my next article. ‘Coconut or Coconot: That is the question’ (I am already quite fond of the article purely because of its title alone!)
Dairy fats are also being reviewed and recommendations considered by professional bodies through out the world. To the best of my knowledge the Heart Foundation and Dietitians NZ have people looking at this as well. So it is a watch this space type thing. I will wait for the experts to come up with an expert opinion.
Personally I think that this change in thinking is going to make things a little bit tricky when it comes to the making of recommendations for the eating of actual food. If you have had a look at my previous article that tackles the basics of fats and oils in our diet you will know that when it comes to the fat found in food, one food doesn’t contain just one fatty acid or even one fatty acid group. The fats we eat in food form are an eclectic bunch. So I suspect the future will be more research, more research and a bit more research.
The Now: In My Kitchen
Ok, so where does that leave me as a mum with a background in human nutrition what am I doing?
Well firstly I don’t think we should just through the baby out with the bath water. Not everything we have learnt and done in the past is necessarily wrong, the new evidence just shows there might be some valid ‘changes, tweaks and potential relaxations’ to be made to current recommendations.
To me the existing evidence still seems pretty convincing on a number of fronts, including but not limited to:
- Olive oil reduces heart disease risk
- Nuts and seeds included in a healthy diet reduces heart disease risk
- Oily fish included in a healthy diet reduces heart disease risk
Common sense also tells me that we should be cutting out the crap. No matter what the fat type, piles of fried foods and high fat processed items are probably not going to confer any health benefits
When it comes to the use of other fats in oils in my household I stick with a ‘use the best one for the job’ philosophy. This means I use a mixed bag. I pick fats and oils not purely because they will confer health benefits but also because they just make things taste good and make a great end product. Fats and oils not only add flavour to foods they also enhance the flavour of other ingredients as well, they are flavour carriers. By using a mixture I am essentially hedging my bets, covering all bases but making sure my food tastes fantastic at the same time.
- I use a strongly flavoured oil when I am making a salad dressing (Extra virgin olive oil, avocado walnut oil)
- So many of my dishes start with onions and garlic , and usually olive oil
- I use butter when I bake
- I use coconut oil when I am making a curry or satay, it makes them taste devine, and onions saute beautifully in coconut oil
- I add a dash of sesame oil to asian dishes, it is just so delicious
- When I’m bbqing I use an oil with a high smoking/flash point (Rice bran or avocado oil)
- I use olive oil in pasta dishes and when I make pesto etc, if you are going italian then stick to the traditional I say
- I add nuts and seeds to meals I make. They go into salads, into stir-frys and we have them regularly as snacks.
- Avocado is a common spread on sandwiches
- We eat oily fish, usually salmon quite often
So there you have it my updated view on fats and oils for heart disease. In essence the changes haven’t changed my eating habits a great deal. But I will wait with interest to see what future research brings to the table.
Next up I will be tackling Coconut oil so check back in if thats a topic that interests you. Sign up to my newsletter and I’ll make sure you hear about any updates and giveaways I might have going on.
p.s Obviously I have simplified the concepts and used a touch of creative licence to illustrate my points (the body is complicated so I’v stuck with generalisations rather than getting into every nitty gritty detail) , but hopefully it all makes sense.
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My Kids Lick The Bowl is a blog written by Stacey I am a mum of 3 young children and qualified nutritionist living in Tauranga, New Zealand. With 5 years of Human Nutrition University study and 10 years working as a Dietitian you can trust the food, nutrition and healthy eating advice you find on my site. I regularly post recipes, practical evidence based articles and reviews of products I love. Occasionally I branch out and record my random musings on life as a mum with 3 children 3 years and under. You can find my best bits so far in my gallery I’m determined to bring common sense and practicality to feeding kids.0