What has cholesterol ever done for us?

It’s National Cholesterol Month! It was probably created (who does decide these things?) to raise awareness to the ‘dangers’ of cholesterol. Today I’d like to make a plea for cholesterol – probably not what National Cholesterol Month is meant to be about, but here goes …

What comes to mind when you hear the word “cholesterol”? Most likely eggs, bacon, lard, clogged arteries, heart attack, stroke. Something along those lines.

Now for a list of positive associations …

Anything?

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Cholesterol has had a really bad rap over the last 60 years or so, so much so that hardly anyone can think of anything good to say about it. So, is cholesterol a dangerous substance that somehow accumulates in our arteries, only to kill us in the end? What is it? Where does it come from? What does it do?

 

What is cholesterol?

Cholesterol is a lipid, a waxy substance produced in the liver and all body cells except nerve cells, but there is a special type of brain cells that makes cholesterol, too, because the body’s cholesterol cannot cross the blood-brain barrier. “So, hang on,” you might say “the body makes it? If it’s so bad for us, why?” Exactly. The body does of course produce lots of substances that are bad for us – waste products that occur in normal metabolism and that need to be detoxified -, but cholesterol is not one of them. It has a purpose, several actually, and it is a vital substance.

 

What does cholesterol do?

Cholesterol is a component of every single cell membrane in the body. It is like a wedge that holds cell membranes together, giving them both stability and the fluidity they need to function. Cholesterol is needed to repair existing cells as well as to make new ones. Any kind of trauma, injury or surgery triggers an increase in cholesterol production, because it is needed for repair.

All steroid hormones, for example cortisol, oestrogen and testosterone as well as neurotransmitters, are made from cholesterol, and so is vitamin D. Steroid hormones regulate energy production, metabolism, hydration, reproduction, behaviour and emotions, the formation of brain, muscle and bone. All rather important … Vitamin D is needed to make healthy bone, protects us from cancer and heart disease, high blood pressure and arthritis.  

The brain makes up 2% of our body weight, but contains 25% of the body’s cholesterol. The substance is part of the myelin sheath, the fatty insulation of nerve cells and allows them to transmit impulses. They would not function without cholesterol.

Cholesterol is a major component of bile, an emulsifier made in the liver that is needed for the proper digestion of fat.

Cholesterol is even involved in immune function. It is found in high concentration in ‘memory cells’ – those cells of our immune system that ‘remember’ a pathogen encountered before. They recognise it and raise the alarm, triggering an immune response.

 

Can cholesterol be too low?

Smith-Lemli-Opitz Syndrome (SLOS) is a rare genetic condition affecting cholesterol synthesis – children born with this are severely disabled and have a low life expectancy as the brain is underdeveloped. Somewhere between ‘too high’, ‘healthy’ and ‘death’ there has to be a ‘too low’, you would think.

Low cholesterol may contribute to forgetfulness, disorientation, confusion – often seen as normal signs of ageing. The American astronaut and NASA doctor Duane Graveline experienced retrograde amnesia when his cholesterol had been lowered by statin drugs. He was temporarily unable to remember his home address, recognise his wife and children, or remember his job. He stopped taking the drug and his brain function returned to normal. Dr Malcolm Kendrick has written about Dr Graveline on his blog.

Studies have found higher rates of death from unnatural causes (suicide, manslaughter, murder) in people with low cholesterol levels (⩽165 mg/dl or 4.2 mmol/l) (1).  

What’s more: Elevated cholesterol levels appear to be protective in older people. A 2017 systematic review of the literature (3) found that high LDL cholesterol is inversely related to mortality in people over 60 years of age, meaning: the higher your LDL once you’re over 60, the longer you live. This is most likely – as more than a dozen of the reviewed research papers found –because LDL binds to and inactivates a broad range of microorganisms and their toxic products. In other words: Cholesterol protects the elderly from infectious diseases. The full text of this review is available online. Click here to read it.

Considering how vital cholesterol is for life, it stands to reason that it can indeed be too low. Low cholesterol is associated with a number of diseases, but is most commonly caused by statin drugs. It’s not easy to find literature on where the bottom line is, but what little research there is puts it at around 4.0 mmol/l (2, 3). 

So there you have it. Cholesterol is not all bad. In fact it seems to be more good than bad.  

Just in time for National Cholesterol Month, Dr Mark Hyman welcomed British cardiologist Dr Aseem Malhotra on his podcast “The Doctor’s Pharmacy” this week. It’s not all about cholesterol, in fact it is more about bias in research - the two cover a lot of ground - but either way it’s worth having a listen. Click here for the podcast.

If you would like to learn more about cholesterol, here’s a handy reading list of books that take a critical view on the current paradigm.

 

(1) Psychosomatic Medicine 2000;62 - Epidemiology 2001 Mar;12:168-72 - Annals of Internal Medicine (1998;128(6):478-487), The Journal of the American Medical Association (1997;278:313-321)

(2) Nago et al (2011): Low cholesterol is associated with mortality from stroke, heart disease, and cancer: the Jichi Medical School Cohort Study. Journal of Epidemiology 2011:21(1):67-74.

(3) Ravnskov et al (2017): Lack of an association or an inverse association between low-density-lipoprotein cholesterol and mortality in the elderly: a systematic review. BMJ Open 2016;6:e010401. doi: 10.1136/bmjopen-2015-01040 (Free Full Text)

(4) Hamazaki T, Okuyama H, et al (2015): Towards a Paradigm Shift in Cholesterol Treatment. A re-examination of the Cholesterol Issue in Japan. Ann Nutr Metab 2015:66 Suppl 4:1-116. doi: 10.1159/000381654

(5) Lv YB, Yin ZX et al (2016): Serum Cholesterol Levels within the High Normal Range Are Associated with Better Cognitive Performance among Chinese Elderly. J Nutr Health Aging. 2016 Mar;20(3):280-7. doi: 10.1007/s12603-016-0701-6. (Free Full Text)

(6) Mufti RM, Balon R, Arfken CL (2006): Low cholesterol and violence. Psychiatric Services

(7) Ravnskov, Uffe (2003): High cholesterol may protect against infections and atherosclerosis. Qjm 96.12 (2003): 927-934. 

(8) Ravnskov U, McCully KS, Rosch PF (2011): The statin-low cholesterol-cancer conundrum. QJM (2011): hcr243

 

 

 

 

Ketogenic Diets are back

You’ve probably read the headlines and wondered whether you should take the plunge if the results – steady and sustainable weight loss and improvement of health markers - are really that dramatic and that easy. But are they, though? This post will give you the inside line on what the diet involves, whether it’s healthy and even sustainable for ‘normal’ people. Here goes …

The ketogenic diet is the ultimate low carb diet. It advocates a moderate protein intake and is very high in fat. It is similar to the Atkins diet, but it as a more modern version of it, now with a solid scientific basis. Both are very low carbohydrate diets, but the Atkins diet tends to be higher in protein, whereas keto somewhat restricts protein in favour of fat. Recent research over the last decade or so has provided evidence of the therapeutic potential of ketogenic diets in many health conditions, including diabetes, polycystic ovary syndrome (PCOS), acne, neurological conditions - particularly epilepsy - and the management of respiratory and cardio-vascular risk factors.

Although dieters tend to lose weight, there is more of an emphasis of the ketogenic diet as a therapeutic diet, which may improve compliance for those that follow it for health reasons.

Like the Atkins diet, the ketogenic diet aims at keeping the body in permanent ketosis. Let’s take a look at what that actually is …

Glucose is the easiest molecule for your body to convert and use as energy so that it will be chosen over any other energy source. Insulin – a hormone made in the pancreas – is produced to process the glucose in your bloodstream by taking it into the cells. It’s the fat-storage hormone produced in direct proportion to the type and quality of carbs consumed. When you lower the intake of carbs in your diet, you force the body into a state of ketosis.

Ketosis is a natural process that helps you survive when food intake is low. When in this state, you produce ketone bodies or ketones, which are produced from the breakdown of fats in the liver. They are an alternative source of energy, when glucose is not available. Energy from ketones works just as well and feels no different – better, if anything, and the brain actually prefers ketones.

 Photo by  Katherine Chase  on  Unsplash

Photo by Katherine Chase on Unsplash

What do you eat?

The ketogenic diet is largely based on protein and fat, and is filling and satisfying. This means no hunger cravings and consistent energy levels.

The downside is the diet is very strict. Cutting out carbs means more than just avoiding the bread, pasta, rice and potatoes that we think of as carbohydrates, but also other foods including many fruits and a number of starchy vegetables and even some nuts, such as cashews. What you might not be prepared for is having to cut back on alcohol. It’s not about cutting it out entirely – spirits are OK, but you have to watch the sugary mixers, and champagne and wine are not so bad in moderation, but a lot depends on your individual sensitivity to carbs. Your favourite cappuccino or latte may also be out.  

 

IN

Meat, fish, poultry, eggs.

Leafy Greens like spinach and kale.

Above-ground vegetables like broccoli, cauliflower, leeks, peppers, etc.

High Fat Dairy like hard cheeses, cream, butter, etc.

Nuts and seeds 

Avocado

Berries – raspberries, strawberries, blueberries blackberries, and other low GL berries

Other fats – coconut oil, high-fat salad dressing, saturated fats, etc.

 

OUT

Grains like wheat, rye, oats, corn, rice, barley.

Pulses such as chickpeas, soya, kidney beans, lentils.

Sugars: honey, agave, maple syrup.

Fruit like apples, bananas, oranges.

Potato, sweet potato, carrots, beetroot, etc.

 

Getting into ketosis

For most people, a ketogenic diet means that carbs are restricted to no more than 20g per day, however not everyone is equally sensitive to carbohydrates and some can get away with up to 50g. You’ll have to test where your carb threshold lies by measuring ketone bodies in the urine, blood or breath.  

You might be reading this thinking, ‘I can do this’, but the reality can be very testing. It can, in fact, take 4 weeks to get there and during the transition period many experience ‘keto flu’ – flu-like symptoms, headaches, tiredness, and weakness. This happens when the body runs out of glucose and has not yet learned to switch to using fat for energy – that’s because it hasn’t had to for such a long time. Until you become ‘fat adapted’ (i.e. your body has re-learned to use fat), there is a period of low energy. It is this taxing time that can put people off.

The people that do best on a ketogenic diet are those with a really compelling reason to do it, perhaps one of the chronic health conditions this diet can help. The rest of us mere mortals may struggle to be committed enough to get into and stay in ketosis. At the same time, be aware that the ketogenic diet may not be for you, for example if you are on insulin or blood pressure lowering medication. Make sure to educate yourself first to be safe.

If you are keen to find out more about ketogenic diets or if you'd like to book a complimentary call to discuss which approach to weight loss would best suit you, please do get in touch.

 

Gotta love fat

Park that notion that fat is bad. It is not. In fact, most of us aren’t eating enough of it. Fat can help you lose weight, protect against heart disease, absorb vitamins and boost your immune system.

Here’s why fat is essential in the body…

  • It’s a concentrated energy source.   Gram for gram, fat is twice as efficient as carbohydrates in energy production. Or in other words: fat has twice the calories of carbohydrates or protein, and here lies the problem: If we believe that a calorie deficit (calories in < calories out) is required for weight loss, then obviously the easiest way to achieve that is by reducing fat.
  • Fat can be an energy store. Excess fat is stored for future energy production (excess calorific intake). We can only store very little carbohydrate and no protein.
  • Protection – internal (visceral) fat protects your internal organs, like the kidneys and spleen. Too much of it is not desirable though, because we now know that this kind of fat secretes pro-inflammatory chemicals, making us sick.
  • ‘Subcutaneous adipose tissue’ (that’s code for the fat that you can feel by pinching your skin) helps to maintain normal body temperature and provides padding. Who wants to sit on their pelvic bone?
  • Fats regulate inflammation, mood and nerve function.
  • Every cell membrane in our body is made of fat – the brain is 60% fat. Without fat, there is no life.
  • Many hormones are made from fat. These are known as steroid hormones and they govern stress, sex, and immune function.  
  • Fats are actually essential for survival (experiments on rats in the 1920s showed that, then fat was removed from the diet they died).
  • Fat is the preferred fuel for muscles and the heart. The brain can also burn fat for fuel.
  • Essential fatty acids are required for healthy skin, healthy cell membranes, healthy nerves, healthy joints and to help with absorption of fat-soluble vitamins A, D, E and K.

In the world of nutrition “essential” means: We need to eat it, our body can’t make it. There are essential fats (omega-3 and omega-6), there are essential amino acids (building blocks of protein), but there are no essential carbohydrates. Do you think there’s a clue there?

How did fat get such a bad name?

Fat has got a bad reputation. Over the last 70 years low-fat products have been marketed as the saviour of our health. And the message from governments and the media was – and largely still is – that, when eaten, fat gets stored as fat in the body and puts us at greater risk of heart disease. However, when it comes to the human body, things are hardly ever that simple, and they are not in tis case either.

Part of the problem, of course, is that we use the same word for the fat we don't want (on the hips, around the middle and so on) and the fat we eat. Our current dietary guidelines imply that if we don’t eat (much) fat, we won’t get fat. Have a look around you and check how well that is working for us. If you listened to The Food Programme this week you will have heard Prof. Louis Levy of Public Health England (the people behind the Eatwell Guide) say:

The real thing about the Eatwell Guide is that it’s there to help people understand what a healthy diet is. What it won’t do is make you eat it.
— Prof. Louis Levy, Public Health England

So there we have it: If you are overweight or obese, suffer from diabetes and/or heart disease then evidently that’s your own fault. If only people would do as they're told already, we would not have a major public health crisis. Yet, statistics show that we actually have listened: We are eating less meat and butter, buy a lot more low-fat products than we used to and base our diets around carbohydrates – just as instructed. I see it in clinic every day: Clients tell me that they do follow a healthy diet, they are cutting the fat off their meat or avoid meat altogether - let alone butter or cream - and always go for low-fat yoghurt, cheese, hummus and guacamole. But it's not working! Obesity researcher Zoe Harcombe has taken apart the SACN report Prof Levy quotes in the interview. If you would like to read it, click here, but the gist is that the evidence Public Health England claims to have based the Eatwell Guide on does not actually hold up.

The demonisation of fat began when an American scientist called Ancel Keys produced the first ‘evidence’ linking saturated fat to heart disease in 1953. He based his scientific opinion on observational data of heart disease, death rates and fat consumption in six countries (ignoring statistics from a further 16 countries because they contradicted his hypothesis) and assumed a correlation between heart disease and eating fat. (As an aside, when another scientist looked at the same research, this time considering all 22 countries’ data, no correlation was found. The data is still available and what researchers now find is that there is actually a much stronger correlation between sugar consumption in all of the countries! A possibility that Keys did not even consider.)

Although there might have been correlation between saturated fat consumption and heart disease (there was a relationship), it was not causal (didn’t actually cause the situation).

A further study on rabbits compounded Ancel Keys’ hypothesis: The rabbits were fed cholesterol (which doesn’t normally form a part of their 100% veggie diet) and went on to develop fatty deposits in their arteries. And then, guess what happened? Poor bunnies!

Governments (and their health care agencies) across the world began advocating a low fat diet on the basis of this flawed research.  They told us to fill up on bread, rice, cereals and pasta, and opt for low-fat or no-fat alternatives wherever we could. And we did. 

Soon, the food industry jumped on board to create products that better satisfied this new advice. They replaced saturated fats with ‘healthier’ vegetable oils, like margarine and shortening – ironically trans fats are now one of the few fats research shows are linked to heart disease. The biggest problem is that, when you remove the fat from foods, you need to replace it with something else to make those foods palatable – and this replacement is sugar. This was a really bad move.

We have been ‘good’! People around the world have listened to the low-fat recommendations since the 1970s and put them into practice. And it is from that point onwards that obesity, diabetes and heart disease really took off. Go figure!

To cook or not to cook

To cook or not to cook?

My clients often ask me whether it’s better to eat their food – particularly vegetables – cooked or raw. It’s not one or the other, it’s both, really. Raw vegetables, especially if eaten or frozen very soon after harvest, contain more vitamins than cooked. Scientists think that the discovery of cooking might even be what gave humans the edge over other primates: It allowed us to consume a lot more food – and thus calories – which then enabled us to grow a bigger (and very hungry) brain. Moreover, cooking of course reduces the risk of infection as it kills most microbes.

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Yes, vitamins tend to degrade through cooking (and storage), minerals are indestructible, but they, too, may be lost if you throw out the water you cooked your veg in. However, all the vitamins in your vegetables will do you no good if you cannot absorb them. You are, after all, not so much what you eat, but what you absorb. Some foods even contain ‘anti-nutrients’, compounds that can be harmful if overconsumed, and cooking or soaking can render those harmless or reduce the amounts present in the food.

Carrots, for example, are not easy to digest. They are a good source of beta-carotene, a phytonutrient (plant nutrient) that is converted into vitamin A in the body. But you must first be able to absorb it, and that is easier when the carrots are steamed or roasted. Add a little olive oil, because beta-carotene is fat soluble and needs fat for proper absorption.

Tomatoes contain a phytonutrient called lycopene. It is responsible for the tomato’s red colour. Lycopene is thought to protect the arteries from oxidative damage and is anti-inflammatory, and cooking significantly increases the absorbability of lycopene, so don’t eat all of your tomatoes raw, make sure to have some cooked, whether that’s as tomato sauce, soup or in a casserole or on a homemade pizza.

Cruciferous vegetables (cabbage, cauliflower, broccoli, kale etc.) contain nutrients called sulforaphane and indole-3-carbinol, which are said to have cancer protective properties. These are made available when you simply chop the veg … but are destroyed by heat. So, to make the best use of those nutrients, you would want to eat your cruciferous veg raw. The downside of that is that they also contain goitrogenic compounds, which can affect the thyroid. Cooking renders those harmless. So, it’s a bit of a toss-up, depending on what you need and how healthy you are. If you have thyroid issues, it is best to limit raw brassica, but if you are healthy, you’d have to eat an awful lot for the goitrogens to affect your thyroid. The best of both worlds may be to lightly steam and soften the veg, which will still preserve some of the sulforaphane and I3C.

Green leafy vegetables, such as spinach, watercress, rocket, and kale, are a great source of vitamins and minerals, especially vitamin C, B vitamins (incl. folic acid), vitamin K, magnesium and calcium and of course fibre. Vitamin C is very sensitive and quickly diminishes once a vegetable is harvested. Heat reduces vitamin C even more and folic acid is lost as well when the leaves are cooked, so salads and raw green smoothies sound like a good idea. But green leaves are also a source of oxalic acid. Oxalic acid interferes with the absorption of minerals, such as calcium, magnesium and iron – the very nutrients that are so abundant in green veg. Oxalic acid also contributes to the formation of kidney stones, so if you have had problems with those in the past, you’ll want to be more careful. Cooking the leaves destroys the oxalic acid, while – remember – leaving the minerals intact and then ready to absorb. Now, don’t let me scare you: A couple of handfuls of green leaves per day are not going to kill you. Rotate your leaves (i.e. don’t eat the same every day) as different plants contain different types of oxalates. Make sure to cook some of your leaves, too, for the improved absorption of minerals.

Mushrooms, too, are not easy to digest. Their cell walls don’t break down easily, so it’s really quite difficult for us to get to the nutrients they contain. Again, cooking helps us out, breaking down the cell walls for us. And a rather peculiar thing happens with mushrooms: While normally vitamin C decreases with cooking, in mushrooms it increases – at least in shiitake mushrooms.

Whole grains, beans, lentils and nuts contain a substance called phytic acid. If it binds to minerals in the gut, it takes prevents them from being absorbed and they will be excreted in the waste. This could, for example, affect your iron levels. Cooking, soaking, sprouting and fermenting reduces the amount of phytic acid in foods.

Does cooking decrease fibre? No! Like minerals, fibre is virtually indestructible until it reaches the large intestine, where our good bacteria get to work on it. Processing (chopping, blending, cooking) and chewing breaks fibre down mechanically, making it easier to digest, but it is not going to disappear and will still work its magic in the digestive tract.

How to cook?

Steaming is one of the gentler ways of cooking. Either use a steamer, where your food doesn’t touch the water at all, or cook it in very little water with the lid on. Most veg soften in just a few minutes.

Slow-cooking is a great way to gently cook your veg. The temperature is kept low (that’s why it takes hours) to preserve as many nutrients as possible. As slow-cooked meals are usually soups, sauces, or stews, you won’t be throwing out the water and therefore get to eat the minerals.