22 April 2010

Confusion Over Dietary Fats

I know I said I wasn't going to write about diet but given that there's so much confusion over fats in foods, what fats are good and which are bad, I thought I'd have a dig in my personal archive and summarise it for you.  Think on it as a sort of Fatty-Fatty-Crib-Sheet.

While there is increasing evidence of the protective, curative and life-enhancing benefits of omega 3,omega 6 and omega 9, throughout the Western world, most people consume far too little of the essential fats and far too much of all the others.

Omega 3,6 and 9 fats play a key role in brain development, heart protection and healthy vision. They help relieve allergies and can create periods of remission for those suffering from Crohn's disease, IBS, colitis and ulcerative colitis. Both adults and children with joint pain, asthma, eczema and psoriasis can benefit from the  anti-inflammatory properties of these fats.

They assist our fitness goals by improving stamina and endurance, decreasing recovery times, improving protein and amino acid utilization, increasing metabolic rate, improving oxygen uptake, optimizing glandular function and heightening reflexes and concentration.

Types of Fats

Essential fatty acids

These are polyunsaturated fats and are liquid at room temperature. There are three groups - omega 3, omega 6. EFAs are essential and our bodies cannot manufacture them.

Linoleic, otherwise known as omega 6 fatty acids, are found in most vegetable oils. You don't need much of them and excessive amounts can speed up the growth of cancer cells. Proportions of omegas 3 and 6 are important. Oils with lots of 6 and very little 3 put you in double jeopardy because of the likely cancer-forming properties of the omega 6s and because they also have a negative effect on the heart protection benefits of omega 3.

Alpha-linolenic, or omega 3 fatty acids are the healthiest of all and abound in oily fish and some vegetable oils, especially those made from rapeseed, walnuts and flax seeds. They protect against heart disease and cancer and are very important during pregnancy for the proper formation of the baby's brain cells.

Non-Essential fatty acids

This is the category that Omega 9 falls into.  This is because omega 9 can be created by the body from  unsaturated fats.  Oleic acid (most common omega 9) is associated with a decrease in breast cancer risk.  It is the main component in olive oil and can be found in other monosaturated fats.  It also occurs as Erucic acid in rapeseed, wallflower seed and mustard seed.

Omega 3,6 and 9 Ratio

The ratio at which you intake fats is important.  As is mentioned above, too much 6 can cancel out the benefit of the omega 3s.  The optimum ratio is thought to be 2:1:1 (3,6,9).  The recommended dose for those on a heavy weight training schedule would be 15ml blended per 50lbs of bodyweight.

Buying a blended oil with the right ratios such as Udos oil means it can be added to the food you’re already  eating in order to get the amount you want and consuming it this way is cheaper than getting 15ml in capsules.

Conjugated linoleic acid

Occurs in free-range cattle raised on natural grassland. Has anti-cancer properties and stimulates the human body's conversion of stored fats into energy.

Monounsaturated fats

Olive oil is the most commonly used and, although liquid at room temperature, it solidifies if refrigerated. The  richest sources are olives, olive oil, avocados, walnuts and walnut oil, peanuts and peanut oil. Monounsaturated fats are much better for your heart and can even help reduce cholesterol. They appear to have no role in the formation of cancer.

Polyunsaturated fats

These are liquid even at low temperatures and extracted from plant sources like sunflowers, safflowers,  rapeseed and corn. Generally healthier than saturated fats, these have a high content of omega 6 EFAs in relation to omega 3. This imbalance means we now consume four times more 6s than 3s. Even though 6 is essential, this ratio has been linked to mental and physical disorders.

Saturated fats

Nearly all animal fats from meat and meat products - milk, cream, cheese, butter, lard and suet - go solid at room temperature. These can increase cholesterol which in turn locks arteries and causes heart disease. Though there is little evidence they play a role in the development of cancer, many experts believe that lower consumption reduces the risk.

Trans fats

Do not occur in nature but are the result of a catalytic process to solidify the cheapest vegetable oils used in food manufacture. The resulting hydrogenated fats are used in margarines, take-aways, ready meals, cakes, biscuits, crisps and sauces. Consuming these raises the risk of heart disease. There is evidence that trans fats are linked to a risk of breast cancer.

Off the Supermarket Shelf

Olive oil
Reduces blood levels of cholesterol, contains monounsaturates and is low in omega 6.

Rapeseed, walnut and flax seed oil
All low in saturated fatty acids, substantial monounsaturates and a good source of omega 3 and 6 EFAs.  It should be noted though that flaxseed oil has a ratio of 4:1 omega 3:6 which leaves it a bit low on the omega 6 side.

Coconut and palm oils
Contain large amounts of saturated fats, little monunsaturated and virtually no omega 3. Avoid it.

Can You Get Too Much of the Good Stuff?

In short, no.

When you get more than 12-15% of total calories as n-3s, there is a fat "burn-off" based on increased metabolic rate. Other than exceeding liver capacity and getting nauseous, or not sleeping because of too much energy because you took it too close to bedtime, it doesn't appear so.

In tropical climates too much oil can make people sweat more easily, that’s not necessarily bad, but if you’re heading off somewhere tropical you’ll have to remember you may well need to drink more water.

How much is optimum?

Generally 15-30% of overall calories should come fats and the majority (if not all) of these should come from healthy sources such as fruit, veg, nuts, seeds, fish and meat. 15% is at the lower end of the scale and should only be followed for short periods of time.

Further Reading
For more information I recommend reading any of Anita Beans books , a raft of articles from ultra fit magazine that unfortunately aren't online, new scientist magazines health section, Dr Udos Fat FAQs, Tom Venutos book 'Burn the Fat, Feed the Muscle'.  For great recipies see JAGs Health & Fitness blog and Stella Does Healthy Eating.

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