Time to Chew the Fat - by Dr Nathan Akmens
Fats are encountered on a daily basis in the modern diet. Whether it’s beginning the cooking process in a pan or dressing a salad for lunch they remain a universal feature of our food and its preparation. However there is still much confusion about the impact they have on the body with recent discussion centring on what constitutes healthy and unhealthy sources. In this feature we will examine the true nature of fats and find out exactly what role they play in our health.
What are fats?
Defined simply as a collection of triglyceride molecules. At room temperature this molecular group is designated as FAT if it is solid and OIL if liquid. The chemical structure of all fats contains 3 fatty acids attached to a glycerol backbone as shown below.
Much of our discussion will focus on the fatty acid, as it determines whether the triglyceride is termed saturated, monounsaturated or polyunsaturated. The difference between the three classes is the amount of double chemical bonds within the fatty acid.
- Saturated : no double bonds
- Monounsaturated: one double bond
- Polyunsaturated:several double bonds
In all naturally occurring fats there is a mixture of saturated and unsaturated molecules. These proportions will change across a range of different foods. Beef fat (tallow) for example is
50-55% saturated with the remaining profile unsaturated, which may be surprising for some to learn 1.
We may also come across short chain, medium chain and long chain definitions of fats. As their name implies this refers to the overall length of the carbon structure in the fatty acid seen in the diagram above. There are unique characteristics attributed to them with the most noteworthy being the antimicrobial qualities of short chain fatty acids, and the immune supportive role of short and medium chain fatty acids 1, 4.
What is their role in the body?
Fats are an important macronutrient and play a critical role as a concentrated source of energy in the human diet 2. They also provide the building blocks for all cell membranes including those for the brain, nervous and vascular systems 3, and a variety of hormone and hormone-like substances 4. They have an ability to increase satiety levels by slowing down nutrient absorption, enhance immune and bone health and also act as carriers for the vital fat-soluble vitamins A, D, E and K 4.
Our bodies are unable to manufacture omega-3 and omega-6 essential fatty acids and so we must gain them directly from dietary sources.
When fats go bad?
Certain fats have a bad reputation even in light of the known benefits they provide. For decades now it has been assumed that we should reduce saturated fat intake for optimal health 4. However many of the leading contributors on the subject explain ‘the science has never existed to… demonise saturated fat’ 2 and that they are not ‘the cause of modern disease’ 4.
The health dangers in regards to fat consumption should focus on the tendency of a fatty acid turning rancid when subjected to heat, oxygen and moisture 4.
The factors that will increase the likelihood of oxidation i.e. a fat ‘going bad’ are the presence of double bonds in the internal chemical structure. The more unsaturated a fat, the greater vulnerability it carries for oxidative damage, a pro-inflammatory process characterised by free radical formation that greatly impedes important cellular activity 3. Depending on the site of damage, free radicals have been implicated in the formation of wrinkles in the skin, cancer, and vascular wall damage i.e. cardiovascular disease 4, 5.
This would suggest that the more saturated a fat is the greater chemical stability it will have when exposed to various elements. This means safer storage, safer consumption and safer cooking with fats especially at high temperatures.
The dangerous artificially made trans fats also need to be avoided at all times.
Generated through a process termed hydrogenation, trans fats are the by-products of converting liquid oil to a solid fat 1, 2, 3, 5. Apart from being associated to many diseases, these ‘plastic fats’ 1 promote rampant oxidative damage 3.
Manufactured trans fat is found in foods that use hydrogenated or partially hydrogenated vegetable fats to increase the shelf life and flavour stability of foods. These foods include deep-fried foods, some take-away meals and baked goods, such as pies, pastries, cakes, biscuits and buns. Check the labels carefully and avoid products containing hydrogenated oils.
What are healthy sources?
We must take care with the fats we choose to consume. Dianne Sanfilippo has a great 3-step process in determining what fats we should eat based on:
1 How they are made: - naturally occurring, minimally processed
2) Fatty acid composition: - more saturated = more stable
3) Smoke point: - how hot is too hot before damage occurs 2
Highly saturated fats are great choices for cooking at medium to high heat levels, as they are temperature stable3. These would include:
Butter, ghee, tallow, coconut oil
Although less temperature stable, olive oil is still good for cooking at low temperatures 3. It is much better however in its uncooked form in salad dressings or in the addition of extra oil at the end of food preparation.
Good sources of monounsaturated fats include:
Olive oil, avocado, macadmias, almonds, walnuts, lard
Polyunsaturated fats should be limited to around 4% of dietary intake 5 and avoided for cooking purposes. The omega-6 and omega-3 essential fatty acids should be in a balanced ratio of as close to 1:1 as possible 4. This means avoiding fats containing high omega-6 ratios including the industrially processed and refined soybean, cottonseed, corn, safflower, and sunflower oils. We should source the majority of omega-3 fatty acids from seafood and animal sources 5.
Chris Kresser has put together a great diagram below that outlines this information visually.
Where to learn more?
- The Perfect Health Diet – Paul Jaminet
- Good Calories, Bad Calories – Gary Taubes
- Deep Nutrition – Cate Shanahan
- Know Your Fats – Mary Enig
- Nourishing Traditions – Sally Fallon
- Practical Paleo – Dianne Sanfilippo
- How To Eat, Move, And Be Healthy – Paul Chek
1) Know Your Fats – Mary Enig
2) Practical Paleo – Dianne Sanfilippo
3) The Primal Blueprint – Mark Sisson
4) Nourishing Traditions – Sally Fallon
5) http://chriskresser.com/9-steps-to-perfect-health-2-nourish-your-body – Chris Kresser
Dr Nathan Akmens, was part of the Chiropractic Solutions Team of Chiropractors from August 2012 until May 2015. His special interest was in fitness, health and the Paleo and Primal Lifestyle and he "walked the talk" living a very healthy life. He inspired us all with his commitment to his diet and his chosen lifestyle.
Nathan then left to pursue life interstate and to embark on the "road less travelled" with his partner Renee.
He is currently working in NSW.