Tag: sugar

#DietSpeak: saturated fats – challenging the dogma

Barts-MS rose-tinted-odometer: ★★★

Since my rather neutral “#DIETSPEAK: IS THERE AN IDEAL MS DIET?” post last week, in which I refuse to support any particular MS diet I have had a  torrent of social media abuse about my position. Intriguingly, many people out there have bought into the falsehood that saturated fats are bad for you and some commentators even believe that saturated fats cause MS. The evidence is clearly to the contrary for the former and for the latter the evidence is just not there to draw any causal inferences. In fact, as saturated fat consumption has gone down the incidence and prevalence of MS has increased.  This alone indicates that saturated fat consumption cannot be the cause of MS.

John Maynard Keynes, the famous British economist responsible for ‘Keynesian economics’, is often quoted as saying: “When the facts change, I change my mind. What do you do, sir?”. 

The claim that saturated fat is bad for health was promoted by the now-discredited physiologist and nutritionist Ancel Keys.  His theory was based on his ‘Seven Countries Study’, which has now been discredited with several commentators suggesting that some of the data was made up. There is evidence that of 22 countries that he had data for, he cherry-picked 7 countries so the data would fit and prove his hypothesis. Despite this, he and his collaborators managed to change the dietary guidelines of the world, recommending a low-fat diet to counteract the cardiovascular disease epidemic. Tragically, the rest is history.

Image of Ancel Keys from ‘A decade of diet lies‘ HUFFPOST

The low-fat diet, in particular the low-saturated fat diet, resulted in a caloric switch to carbohydrates, which has seen obesity rates soar and contrary to what was expected cardiovascular disease rates have increased. It is now clear that Ancel Keys was heavily conflicted and was supported by the food industry. Yes, the food industry managed to influence a change in dietary guidelines that have killed tens of millions of people prematurely. I predict that when the dust settles on this issue the food industry will be judged to have behaved much worse than the tobacco industry. 

The good news is that the facts have changed and several recent meta-analyses have been unable to find any evidence that saturated fats are bad for you (please see review below). The studies showing saturated fats are associated with poor health outcomes are confounded by other factors for example the consumption of processed carbohydrates. 

To address the point that saturated fats cause MS you need to go back to causation theory and apply epidemiological principles. I have addressed this topic several times in the past on this blog, mainly in relation to EBV as a potential cause of MS. To prove or disprove causation you have to satisfy as many of the following nine criteria as possible. 

1. CONSISTENCY AND UNBIASEDNESS OF FINDINGS
2. STRENGTH OF ASSOCIATION
3. TEMPORAL SEQUENCE
4. BIOLOGICAL GRADIENT (DOSE-RESPONSE RELATIONSHIP)
5. SPECIFICITY
6. COHERENCE WITH BIOLOGICAL BACKGROUND AND PREVIOUS KNOWLEDGE
7. BIOLOGICAL PLAUSIBILITY
8. REASONING BY ANALOGY
9. EXPERIMENTAL EVIDENCE

When you apply these nine criteria to saturated fat consumption none of them is fulfilled. I, therefore, can conclude that saturated fat consumption is not the cause of MS. On other words, the data disproves the hypothesis.

Another perspective that you can use to tackle this problem is an evolutionary medicine perspective and to look at how our ancestors evolved and what diets they ate. It is clear that our ancestor’s diets were high in saturated fats and as the history of MS suggests it is a relatively new disease it cannot be caused by saturated fat. In fact, if you want to finger a dietary factor you would point at sugar and processed carbohydrates rather than saturated fats.

I wrote a piece on Medium to explain why low-fat diets are potentially bad for you. You may find the evolutionary medicine approach to diet of interest; I think it may prove to be very relevant to MS. 

Astrup et al.  Saturated Fats and Health: A Reassessment and Proposal for Food-Based. J Am Coll Cardiol 2020 Aug 18;76(7):844-857. doi: 10.1016/j.jacc.2020.05.077. Epub 2020 Jun 17.Recommendations: JACC 

The recommendation to limit dietary saturated fatty acid (SFA) intake has persisted despite mounting evidence to the contrary. Most recent meta-analyses of randomized trials and observational studies found no beneficial effects of reducing SFA intake on cardiovascular disease (CVD) and total mortality, and instead found protective effects against stroke. Although SFAs increase low-density lipoprotein (LDL) cholesterol, in most individuals, this is not due to increasing levels of small, dense LDL particles, but rather larger LDL particles, which are much less strongly related to CVD risk. It is also apparent that the health effects of foods cannot be predicted by their content in any nutrient group without considering the overall macronutrient distribution. Whole-fat dairy, unprocessed meat, and dark chocolate are SFA-rich foods with a complex matrix that are not associated with increased risk of CVD. The totality of available evidence does not support further limiting the intake of such foods.

CoI: multiple

Twitter: @gavinGiovannoni               Medium: @gavin_24211

The war on sugar (more posts below today)

Barts-MS rose-tinted-odometer ★★★ 

Just back from the NMSS ‘Pathways to Cures’ meeting in Washington DC during which we pledged to  STOP, RESTORE and END multiple sclerosis. 

The END refers to prevention. We discussed at the meeting modifiable risk factors that could be tackled to reduce the incidence (new cases) of MS and one risk factor childhood and adolescent obesity. One theory has been that obesity affects MS risk by interacting with vitamin D (vD); either by lowering levels due to the breakdown of vD in fat or secondary to systemic inflammation associated with obesity. 

In this genomics study below it is clear that obesity itself increases your risk of MS and is independent of vD levels. 

So how do we tackle obesity and the obesity epidemic? It is clear that obesity is caused by sugar and the change in the dietary guidelines that occurred in the 1970s and 1980s when governments launched a war on fats and started to promote a low-fat diet as being ‘heart-healthy’. We now know that the low-fat diet was wrong and that what was driving heart and vascular disease was processed carbohydrates, in particular, sugar consumption, and not saturated fats. Fortunately, the world is now beginning to acknowledge that saturated fats are healthy and that processed and ultra-processed foods, which are largely made up of carbohydrates and polyunsaturated fats are unhealthy culprits and are what is causing the obesity epidemic. 

This graph shows you the strong association between per capita sugar consumption and obesity. It is extraordinary that politicians are not doing more to tackle global sugar consumption.

Another factor driving obesity is our sedentary lifestyle and reduced exercise. 

To tackle obesity we need governments to declare ware on sugar and the food industry and to put in place national policies to tackle our sedentary lifestyle. This is easier said than done. Politicians are not as powerful as they used to be; most of them rely on lobby money to get elected and once elected they represent the vested interest groups that got them elected. Sadly this often includes sugar money. 

The sugar industry is heavily subsidised, which keeps the price of sugar artificially low. Sugar subsidies interfere with the global market and have resulted in a sugar glut. This is one of the reasons why junk food is so cheap and real-food is so expensive. 

Obesity is not only a risk factor for causing MS it also affects people with established MS.  Obesogenic diets cause a metabolic shitstorm that impacts on MS indirectly. Obesity causes metabolic syndrome (hypertension, insulin resistance, glucose intolerance, diabetes and dyslipidaemia) and a systemic inflammatory syndrome that worsens MS. Therefore, there is a good reason why, if you are obese you should consider doing something about it. 

I recommend you read “Why we get fat and what to do about it”, by Gary Taubes or you can watch one of his lectures on YouTube. Understanding the metabolic issues that underlie obesity will allow you to understand what to do about it.

Then there is the responsibility you have to your siblings, children and relatives. If you have MS your direct family are at increased risk of getting MS and you should get them to modify their risk factors, i.e. make sure they stay slim, or if they are obese they need to lose weight, get them to exercise and to start taking vD supplements. Tell them about the link between smoking and MS; they should either stop smoking or get them to pledge not to start smoking in the future. 

MS prevention is about education, education, education and education begins in the home. We estimate that ~15-20% of new cases of MS could be prevented by preventing childhood obesity and smoking. This is why we need to declare war on sugar and smoking as part of our END MS campaign. Do you agree?

Jacobs et al. BMI and Low Vitamin D Are Causal Factors for Multiple Sclerosis: A Mendelian Randomization Study. Neurol Neuroimmunol Neuroinflamm, 7 (2) 2020 Jan 14.

Objective: To update the causal estimates for the effects of adult body mass index (BMI), childhood BMI, and vitamin D status on multiple sclerosis (MS) risk.

Methods: We used 2-sample Mendelian randomization to determine causal estimates. Summary statistics for SNP associations with traits of interest were obtained from the relevant consortia. Primary analyses consisted of random-effects inverse-variance-weighted meta-analysis, followed by secondary sensitivity analyses.

Results: Genetically determined increased childhood BMI (ORMS 1.24, 95% CI 1.05-1.45, p = 0.011) and adult BMI (ORMS 1.14, 95% CI 1.01-1.30, p = 0.042) were associated with increased MS risk. The effect of genetically determined adult BMI on MS risk lessened after exclusion of 16 variants associated with childhood BMI (ORMS 1.11, 95% CI 0.97-1.28, p = 0.121). Correcting for effects of serum vitamin D in a multivariate analysis did not alter the direction or significance of these estimates. Each genetically determined unit increase in the natural-log-transformed vitamin D level was associated with a 43% decrease in the odds of MS (OR 0.57, 95% CI 0.41-0.81, p = 0.001).

Conclusions: We provide novel evidence that BMI before the age of 10 is an independent causal risk factor for MS and strengthen evidence for the causal role of vitamin D in the pathogenesis of MS.

CoI: this work was done by our Preventive Neurology Unit

Sugar crash

My recent blog post on food coma (14-Jan-2019) not only uncovered another hidden symptom in MSers but has led us to start exploring this phenomenon in our patients and, hopefully, to some evidence-based advice on how to manage the problem. 

In our short web survey on food coma, I was surprised to find that 86% of MSers report this phenomenon with 28 of the 81 respondents (35%) reporting their food coma as being severe or severe-and-incapacitating. When exploring the science I was surprised to uncover that insulin, the hormone that the pancreas releases in response to carbohydrates or sugar, is one of the main mediators of food coma. How could this be when my mother always used to accuse me of having a sugar rush as a child? A sugar rush is a so-called period of hyperactivity that occurs after ingesting too much sugar in a short period of time. 

I was therefore not surprised to read the following well-done metanalysis debunking this piece of dogma. On the contrary, sugar does not cause a sugar rush, but a sugar crash, another term for food coma. 

This and other evidence keeps mounting against sugar and the sugar industry. There seems to be very little reason for anyone to consume sugar or processed carbohydrates in any form. This is why nutritionists have started to refer to processed carbohydrates as empty calories.

So I am going to repeat myself again if you want to select a diet that is healthy for you can I suggest a real-food diet low in carbohydrates, i.e. free of all processed carbohydrates. This means you may need to get most of your calories from fats and proteins. The carbohydrates you eat on the real-food diet will be unprocessed with a low glycaemic index. As a result of this diet, you will keep your insulin levels low and hence you will reduce your postprandial hypersomnolence or ‘food coma’. 

Keeping your insulin levels low will have other positive effects on your health; i.e. it will help you maintain a healthy weight, counteract insulin resistance and hence your chances of developing the metabolic syndrome (insulin resistance, diabetes, hypertension, hyperlipidaemia and obesity) and it should reduce your risk of developing common cancers.

What is there to lose? How easy is it to stick to the real-food diet? You tell me. 

Mantantzis et al. Sugar rush or sugar crash? A meta-analysis of carbohydrate effects on mood. Neurosci Biobehav Rev. 2019 Jun;101:45-67. 

The effect of carbohydrate (CHO) consumption on mood is much debated, with researchers reporting both mood improvements and decrements following CHO ingestion. As global consumption of sugar-sweetened products has sharply increased in recent years, examining the validity of claims of an association between CHOs and mood is of high importance. We conducted a systematic review and meta-analysis to evaluate the relationship between acute CHO ingestion and mood. We examined the time-course of CHO-mood interactions and considered the role of moderator variables potentially affecting the CHO-mood relationship. Analysis of 176 effect sizes (31 studies, 1259 participants) revealed no positive effect of CHOs on any aspect of mood at any time-point following their consumption. However, CHO administration was associated with higher levels of fatigue and less alertness compared with placebo within the first-hour post-ingestion. These findings challenge the idea that CHOs can improve mood, and might be used to increase the public’s awareness that the ‘sugar rush’ is a myth, inform health policies to decrease sugar consumption, and promote healthier alternatives.