Blog
McXtra Care Newsletter | October 2019

Section A

MAIN FEATURE

Understanding types of fats in our diet and body

LIPIDS include all oily, and fatty substances. We take Lipids in our diet as FATS and CHOLESTEROL.

FATS

Fats contain ‘Fatty acids’ which are made of chains of Carbon (C) atoms forming bonds with Hydrogen (H) atoms. Some of the fatty acids may have double bonds in one or more sites in these chains. At these sites the fatty acid chain acquires flexibility and can be bent. Fatty acids are a vital component of the membranes which cover and line all the cells in our body. However only the ‘flexible’ fatty acids can be incorporated and used in the cell membranes.

Understanding Saturated and Unsaturated Fats

Those fatty acids which do not contain any ‘double bonds’ are called Saturated fatty acids. These fats are not flexible and bendable, so do not get incorporated into our cell membranes. Fats get stored as Triglycerides by our body in the liver, muscle, and adipose (fat under the skin and in between body organs). This storage form of fat may be used as a source of energy once carbohydrates (Carbs) are exhausted. It is important to note that excess Carbs in diet are converted and stored as Triglycerides by our body.

Those fatty acids which contain double bonds are called Unsaturated fatty acids or fats. If only one double bond is present, they are Mono-unsaturated and if more than one is present, they are Polyunsaturated fatty acids (MUFA and PUFA respectively).

Just having double bond/s alone does not bestow flexibility on the fatty acid. If both the H atoms are on the same side of the double bond, they are said to be in ‘cis’ configuration while if the H atoms are on opposite sides of the double bond, they are said to be in a ‘trans’ configuration. Flexibility and bendability is present only in the cis configuration which enables incorporation into cells while the trans fats go into storage just like the saturated fats. Most naturally occurring unsaturated fatty acids occur in cis configuration however on deep frying or during processing for packaged foods, the cis configuration is changed to trans (by a process called hydrogenation) which increases the stability and shelf life of these products.

PUFAs are additionally also utilized by our body to make some chemical mediators which play an important role in the process of Inflammation. There are 2 types of PUFA – Omega 6 and Omega 3 (the number reflects the position of the double bond). They should be taken in a ratio of around 4:1 in our diet for effective balance of the inflammatory mediators. However, most diets are low in Omega 3 (produces anti-inflammatory mediators) with this ratio going up to 12:1 to 25:1 in favor of the Omega 6 (produces pro-inflammatory mediators). So it is important to consciously include some sources of Omega3 fatty acids in our diet.

Saturated fatty acids are classified into short chain (less than 6 C atoms), medium chain (6-12 C atoms) and long chain (>12 C atoms). Medium and long chain saturated fatty acids are found in diet, while short chain fatty acids are produced by bacterial action on the dietary fibers in the gut. These short chain fatty acids reduce gut inflammation and strengthen gut immunity, therefore including more fibers (through salads – fruits and vegetables) is beneficial.

Recent research has shown that the long chain fatty acids from diet are easily stored as TGs while the medium chain fatty acids are preferably burned up as a source of energy. So among the saturated fats, medium chain ones are preferable to include than long chain. Coconut oil and Palm oil have 50% and 40% medium chain saturated fats respectively while other sources from meat and dairy have less than 15% medium chain and mostly long chain fatty acids. Coconut oil is also rich in vitamins and minerals so is the preferred one in the saturated group.

So one should include preferably cis unsaturated fats along with some amount of specifically omega 3 fatty acids and some amount of medium chain saturated fats in the diet for an appropriate balance and health.

CHOLESTEROL

Cholesterol is a type of lipid which has an entirely different structure than fats. It has a complex structure derived from the steroid class of substances. Cholesterol is also an important component of cell membranes, and is additionally used by the body to make Vitamin D, bile and hormones.

It is found only in animal foods we take in diet but most of the cholesterol found in our body is synthesized by our body itself (Usually 20% from diet; 80% by body). Due to the important role of cholesterol in our body, the synthesis of cholesterol is meticulously regulated, which means, if less comes in through the diet, the body will automatically synthesize more and vice versa. Therefore, total cholesterol in the body remains almost constant!

Section B

TRENDING FEATURE

Health Impact of Dietary fats on our body

The fatty acids (fats) are stored in the liver as Triglycerides (TGs) along with Cholesterol. Special proteins combine with TGs and Cholesterol and carry them in the blood to other parts of the body from the liver. Proteins combined with Lipids are called ‘Lipoproteins’.

VLDL (Very Low Density Lipoprotein) carries a large amount of TG along with some cholesterol in the blood. After giving off the TG to other storage sites like Muscle and Adipose, the lipoprotein left behind is called LDL (Low density Lipoprotein) which has mostly Cholesterol and some TG. VLDL and LDL (especially the latter) if present in high quantities in blood can form plaques which can lead to blockages of blood vessels (called atherosclerosis).

The smaller and denser LDL has the greatest propensity to form these plaques. The more the number of VLDL and thereby LDL particles circulating in the blood, more is the risk of plaque formation, atherosclerosis and blood vessel blockage (arteries).

The unutilized cholesterol and TG is brought back to the liver by the Lipoprotein called HDL. Therefore, while VLDL and LDL keep the fats in circulation, HDL removes them from circulation and brings back to the liver. That is why VLDL and LDL are called bad cholesterol while HDL is called good cholesterol.

The amount of cholesterol we take in diet has hardly any relevance to the amount of circulating VLDL and LDL particles. Cholesterol plays a supportive role in transporting TGs in blood, and most of the cholesterol body pool remains constant due to well regulated cholesterol synthesis by the body. However more the saturated and trans fatty acids we take in diet, more will be stored in liver as TGs and more will be the released VLDL and thereby LDL particles circulating in the blood.

Therefore, it is not the dietary cholesterol intake but the dietary intake of saturated and trans fats which increases the risk of developing Cardiovascular disease (CVD) due to plaque blockage of arteries which can result in serious conditions like Angina (partial vessel blockage), Heart attack and Stroke (complete vessel blockage). Plaques are made of deposited Lipids (Fats and Cholesterol) with calcium and some trapped blood cells (Red blood cells and platelets).

Though amount of cholesterol intake in diet has no direct risk, most food sources of cholesterol also contain significant amounts of saturated fats. The exceptions here are eggs and shrimp which are now often recommended in diet without any attributed health risk.

Coronary arteries are the blood vessels supplying blood and oxygen to the heart

When we measure blood cholesterol, we do not actually measure the amount of cholesterol in our body. What we measure is the amount of cholesterol in VLDL, LDL and HDL particles circulating in the blood. More the VLDL and LDL and less the HDL particles in blood, more is the cardiovascular risk due to formation of plaques in the blood vessels. Lab reports mainly use amount of LDL and HDL (and sometimes their ratio- Ideal LDL: HDL= 3.5-4), as the risk indicator for vessel plaques. Apart from this total blood Triglycerides is measured which gives us an idea of body’s Fat overload (which in addition to risk of plaques in blood vessels, also signifies increased risk of diseases like Obesity, Diabetes, Fatty Liver, Pancreatitis and Thyroid disorders).

Blood Lipids

Optimal/desirable

Borderline risk

High risk

LDL

<130
<100 (preferable)
>60

130-159

≥160

HDL

40-59 (men)
50-59 (women)

<40 (men)
<50 (women)

Triglycerides

<150

150-199

≥200

All values in mg/dl. Lipid profile is tested after 12 hours overnight fasting

It is important to note that the risk of Cardiovascular disease (CVD) is not considered in isolation based on the lab values of blood LDL, and TGs. The risk increases in proportion to the presence of other CVD risk factors like high BP, Diabetes, Obesity, Smoking, Physical inactivity, Increasing age and Family history/predisposition.

Does high fat load (high blood TGs and LDL) always imply a high health risk?

It is possible that people with high LDL or TGs may never get CVD or plaque related blockages while people with normal LDL may actually land up with plaques. This is due to other CVD risk factors mentioned. If a person is a smoker, or has high blood pressure or diabetes, the component of injury to his blood vessel wall is high. So in such a person even a lower level of LDL can end up forming a significant plaque as compared to a person who doesn’t have any of these risk factors. Similarly, a family history/genetic predisposition, and increasing age (>45 years) may play a role in adding risk. Obesity and lack of physical activity (reduced utilization of carbs/fats leading to more storage) also contributes to increasing CVD risk.

Section C

SPECIAL FEATURE

Health Solutions for Controlling Fats

By how much should one aim to reduce the blood LDL?

The most important intervention if LDL and TGs are high is always reduction in dietary intake of saturated/trans-fat, and a relative increase in intake of PUFAs (especially Omega3).

More the estimated CVD risk, greater will be the needed reduction in LDL. So a CVD risk categorization is usually done based on all individual factors and the target LDL maybe set accordingly like below:

  • • High risk (2 or more risk factors including diabetes or heart disease): LDL target <100 mg/dl (50% reduction
  • • Medium risk (2 or more risk factors): LDL target <130mg/dl or 30-50% reduction
  • • Low risk (1 or no risk factor): LDL target <160mg/dl or <30% (range of 10-25%) reduction

Lipids

Food source

 

Saturated Fats (long chain)

Whole milk, Butter, Cheese, Cream, Meats (beef, pork, lamb), Poultry with skin, Ghee, Lard

AVOID and REDUCE

Saturated Fats (medium chain)

Coconut Oil, Palm oil

INCLUDE in MODERATION

Trans Unsaturated fats

Deep fried foods, fast food, processed-packaged foods like cakes, cookies, pastries, biscuits, fried packaged snacks, margarine, packaged salamis, ham, sausages

AVOID and REDUCE

Cis Unsaturated fats (MUFA and PUFA)

Nuts like Almonds, cashews, peanuts
Avocados, olives, whole grain wheat, eggs, green vegetables
Oils like olive, sunflower, rice bran, sesame, peanut and corn
Omega 3 sources: fish (salmon, tuna, herring, mackerel, trout), oils (canola, soyabean, flaxseed), walnuts

INCLUDE and INCREASE

Cholesterol

Eggs, Shrimp, Crab (contain Cholesterol without Saturated Fats)

The DASH diet described in detail in the previous newsletter volume 5 helps to control fat levels in the body and is apt for managing BP, blood cholesterol/TG, BMI and weight.

What do cholesterol lowering drugs like ‘Statins’ do?

The decision to start a ‘statin’ drug is based on the inability to bring down LDL with diet alone and the degree of one’s CVD risk.

The statins lower the amount of cholesterol our body makes so that irrespective of the cholesterol coming through diet, the cholesterol made by our body is reduced. Lower cholesterol in the liver will lead to lower quantities of VLDL and thereby LDL particles coming out in the blood.

Therefore, the Statin drugs reduce the blood LDL and TGs thereby reducing the risk of plaque formation and CVD. Dietary modifications mentioned have to continue hand in hand. Specific drugs lowering Triglycerides may also be used if one’s fat overload (TG level) comes out to be significantly high. Newer LDL cholesterol lowering medicines on the block include the PCSK9 inhibitor group of drugs.

Cardiovascular disease (CVD) due to plaque related blockage of vessels is a complicated interplay of several factors! But the drive home message at a practical level still remains that we reduce saturated/trans-fats in our diet, and much rather keep our LDL and TG level on the optimal or desirable side!

Mind Tickle

Solve the crossword below with the clues given

Across

1 – It can be of good and bad type in our body

2 – Target LDL is set according to the CVD __________

3 – Heart condition due to partial blockage of vessels

4 – This fat configuration is found in packaged foods

5 – This diet helps to control BP, Fats, BMI and weight

 

Down

1 – Arteries supplying blood and oxygen to heart

2 – Fats get stored in our __________

3 – This kind of fats has no double bonds

4 – Types of PUFAs

5 – Fat deposition in blood vessels forms __________

On the Lighter Side

– Medical content courtesy – Dr Varsha’s Health Solutions

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