McGlothin (CR Way) believes "high fat intake causes cognitive decline"

[Saul]

I took a look at Paul's CR Way stuff -- and saw a post that I find hard to believe.  The study that Paul is quoting is very small; I thought I'd publish it here, hopefully to get the comments of some of our top scholars, such as Michael Rae and Al Pater:

 

High intakes of fat have been linked to greater cognitive decline in old age, but such associations may already occur in younger adults. We tested memory and learning in 38 women (25 to 45 years old), recruited for a larger observational study in women with polycystic ovary syndrome. These women varied in health status, though not significantly between cases (n = 23) and controls (n = 15). Performance on tests sensitive to medial temporal lobe function (CANTABeclipse, Cambridge Cognition Ltd, Cambridge, UK), i.e., verbal memory, visuo-spatial learning, and delayed pattern matching (DMS), were compared with intakes of macronutrients from 7-day diet diaries and physiological indices of metabolic syndrome. Partial correlations were adjusted for age, activity, and verbal IQ (National Adult Reading Test). Greater intakes of saturated and trans fats, and higher saturated to unsaturated fat ratio (Sat:UFA), were associated with more errors on the visuo-spatial task and with poorer word recall and recognition.


 Unexpectedly, higher UFA intake predicted poorer performance on the word recall and recognition measures. Fasting insulin was positively correlated with poorer word recognition only, whereas higher blood total cholesterol was associated only with visuo-spatial learning errors. None of these variables predicted performance on a DMS test. The significant nutrient-cognition relationships were tested for mediation by total energy intake: saturated and trans fat intakes, and Sat:UFA, remained significant predictors specifically of visuo-spatial learning errors, whereas total fat and UFA intakes now predicted only poorer word recall. 

Examination of associations separately for monounsaturated (MUFA) and polyunsaturated fats suggested that only MUFA intake was predictive of poorer word recall. Saturated and trans fats, and fasting insulin, may already be associated with cognitive deficits in younger women. The findings need extending but may have important implications for public health.

 

PMID: 24376410    --  Saul

 

[Gordo]

Fat from what sources and what is considered high? SAD high fat = meat & dairy & fried/processed foods. We already know those are bad right? This is far removed from "high fat" via mixed nuts, walnuts, chia/flax seeds, EVOO and avocados.

[AlPater]

Comments notwithstanding, the below paper is at least a prospective study versus the one you introduced, Saul.

 

Dietary fat types and 4-year cognitive change in community-dwelling older women.

Okereke OI, Rosner BA, Kim DH, Kang JH, Cook NR, Manson JE, Buring JE, Willett WC, Grodstein F.

Ann Neurol. 2012 Jul;72(1):124-34. doi: 10.1002/ana.23593. Epub 2012 May 18. Erratum in: Ann Neurol. 2012 Oct;72(4):627.

PMID: 22605573 Free PMC Article

Abstract

OBJECTIVE:

A study was undertaken to relate dietary fat types to cognitive change in healthy community-based elders.

METHODS:

Among 6,183 older participants in the Women's Health Study, we related intake of major fatty acids (saturated [sFA], monounsaturated [MUFA], total polyunsaturated [PUFA], trans-unsaturated) to late-life cognitive trajectory. Serial cognitive testing, conducted over 4 years, began 5 years after dietary assessment. Primary outcomes were global cognition (averaging tests of general cognition, verbal memory, and semantic fluency) and verbal memory (averaging tests of recall). We used analyses of response profiles and logistic regression to estimate multivariate-adjusted differences in cognitive trajectory and risk of worst cognitive change (worst 10%) by fat intake.

RESULTS:

Higher SFA intake was associated with worse global cognitive (p for linear trend = 0.008) and verbal memory (p for linear trend = 0.01) trajectories. There was a higher risk of worst cognitive change, comparing highest versus lowest SFA quintiles; the multivariate-adjusted odds ratio (OR) with 95% confidence interval (CI) was 1.64 (1.04-2.58) for global cognition and 1.65 (1.04-2.61) for verbal memory. By contrast, higher MUFA intake was related to better global cognitive (p for linear trend < 0.001) and verbal memory (p for linear trend = 0.009) trajectories, and lower OR (95% CI) of worst cognitive change in global cognition (0.52 [0.31-0.88]) and verbal memory (0.56 [0.34-0.94]). Total fat, PUFA, and trans-fat intakes were not associated with cognitive trajectory.

INTERPRETATION:

Higher SFA intake was associated with worse global cognitive and verbal memory trajectories, whereas higher MUFA intake was related to better trajectories. Thus, different consumption levels of the major specific fat types, rather than total fat intake itself, appeared to influence cognitive aging.

[mccoy]

Thanks for the reference AlPater, Very interesting that MUFAs appear to be protective against cognitive decline. So, in the case of EVOO, it wouldn't be just the phenolic compounds, rather (probably in addiction to that) the quality of dominant fat itself. The above is the first thought which occurs to me, whereas I'll have to read the whole paper to see what's the total fat intake and its variability in that group.

[Sibiriak]

Mccoy:  Very interesting that MUFAs appear to be protective against cognitive decline. So, in the case of EVOO, it wouldn't be just the phenolic compounds, rather (probably in addiction to that) the quality of dominant fat itself.

 

That wouldn't be surprising since it's not phenolics  which are implicated in EVOO's well-known  cardiovascular-protective effects, but also the oleic acid,  b-sitosterol, tocopherols, and terpenoids. See the  article I linked in the EVOO thread,"Cardioprotective and neuroprotective roles of oleuropein in olive".

[mccoy]

Sibiriak, I started to see those publications and sure the EVOOs chemistry is a convoluted one!  As far as I understand, Oleuropein is regarded as a phenolic compound, a phenyletanoid of the secoiridoids group, although I must confess that I didn't grasp perfectly its chemical structure. I insist on the secoiridoids since they have been singled out in the Spanish publication on xenohormesis and are among the most often beneficial compounds cited in EVOO.

 

And I agree that in such a natural mixture we hardly know which are the compounds which have the most impact on health and they are probably synergistic anyway. Tocopherols are a main factors, they are very high in Italian EVOOs. Squalene is a triterpene also common in Italian oils!!

 

I'm reading the article posted by AlPater, but we don't know the foods ingested, so it's nto possible to single out the sources of MUFAs, since the WHS took place in the US, maybe it is not sure that EVOO was the prevalent source of MUFA, as it would be in the Mediterranean countries.

 

That paper is based on a questionnaire, although a detailed one, so it may suffer the known afflictions of questionnaires.

 

I'm also trying to understand whether total fat consumption has been considered in the studies, there is some tables but evidently the breakout into the single fat types is more significant to the topic.

[Sibiriak]

McCoy,  there is a mistake in my  comment above due to careless editing.  

 

I had intended to write,  "it's not just phenolics",   instead of  "it's not phenolics".   ("not just...but also...")

 

You are surely right  that  oleuropein and its metabolites and other phenolic compounds play a central role.   

[mccoy]

np Sibiriak, sometimes we write in a hurry, I myself happened once to write exactly the opposite of what I meant! And I'm also convinced about the sinergy with other compounds, reason for which often extracts of single phytochemicals do not seem to be so effective as the natural mixture.

[Saul]

Hi Al!

Thanks very much for your thoughtful reply!

The results you cites are what I expected -- Paul's post on his CR Way blog was based on a reduculously small study.

I'm surprised that Paul takes it seriously.

-- Saul

[Todd Allen]

I doubt fat by itself is causing cognitive decline.  There are many papers on neuroprotective effects of ketogenic diets.

[Saul]

Yes.

[Sibiriak]

Todd Allen: There are many papers on neuroprotective effects of ketogenic diets.

 

What papers can you cite that demonstrate  neuroprotective effects from  long-term ketogenic diets in normal, healthy adults?  Thanks in advance for any info.

[Todd Allen]

Sibiriak, unfortunately the number of papers meeting those criteria is the same as the number demonstrating long-term health benefits of caloric restriction of normal healthy adults, ie zero.  The vast majority of papers looking at neuro-protective effects of a ketogenic diet are studies of people with afflictions such as epilepsy, autism, alzheimer's, parkinson's, diabetes, etc. and the diet's impact on improving or curing those conditions.  There are case reports of people such as Charlie Abrahams put on a keto diet in 1993 at the age of one after multiple medications and brain surgery failed to control his severe epilepsy who is thriving today and living seizure free.  And like the CR community there is a keto community with apparently healthy long term practitioners some reaching back to the time of the Atkins diet craze espousing the many benefits.

[mccoy]

But Todd, again, in healthy people a keto diet appears to exhibit no advantages. It's Ok to loose weight, to treat some mental conditions you cite, to treat diabetes and cancer maybe, but for longevity and healthspan purposes there is no literature that I know of. At least CR has been shown to be life-prolonging in worms, flies and rats.

[Todd Allen]

Mccoy, there are also apparently healthy people, endurance athletes, going keto for enhanced athletic performance.

 

I believe the research on keto diets answers the original question "does high fat cause cognitive decline?" with a compelling no.  Many consider 45% of calories from fat to be a high fat diet, but it can also still be a high carb diet.  Fat in combination with carbohydrates has been shown to elevate the insulin response of the carbs which is curious because fat lowers the insulin response of protein while fat is largely insulin neutral in isolation.

 

Hyperinsulinemia has been shown to be a factor in many issues such as inflammatiion, vascular disease and a variety of neural/brain disorders.  My answer is the carbs are the problem.  Others may argue fat is the problem.  For many it may be the combination plus caloric excess, but I believe genes play a big role in who has issues with either carbohydrate or fat metabolism.

[mccoy]

Todd, I've read about the experimentation on athletes and soldiers, but I'm not aware of great results. Theoretically, if an endurance contest had rules against ingesting energy drinks and food on the run, a keto diet should give a definite benefit. However, I'm not aware of such contests yet so the theory cannot be proven. The winners are mostly hi-carbs people, who ingest maltodextrin gels while competing. I'd also be interested to see the results on the military personnel. A keto diet would be invaluable since the commandos would be able to operate efficiently without food for days. Maybe it's classified...

 

Also, Keto diets may be very effective in loosing weight, but they don't work with everyone. My wife lost 14 pounds with such a diet, then hit a plateau and never went below that with the same diet, no matter the restrictions. After that, the low fat-low calories diet she tried caused a further 2-3 pounds loss, then another plateau. Both regimens seemed to be unsuccessful in achieving the ideal weight.

 

I lost weight with a low-carb diet but too much and not only fat, I lost muscle mass even though I was exercising.

 

All in all, I was hoping for better results from a ketogenic diet, in my case and in the case of my wife the promises were not kept.

[Sibiriak]

There doesn't seem to be much evidence, if any, that "going keto" enhances athletic performance.  There may be individual exceptions of course.  In some cases, it may make things worse.

 

The Journal of Physiology (2017)
Low carbohydrate, high fat diet impairs exercise economy and negates the performance benefit from intensified training in elite race walkers

 

http://onlinelibrary.wiley.com/doi/10.1113/JP273230/pdf

 

An alternative view on the optimal fuel support for sports performance  [...] is to maximise the contribution of fat as a substrate for exercising muscle by following a low CHO, high fat diet (Noakes et al. 2014; Volek et al. 2015). A key argument in favour of this notion is that even the leanest athlete has an abundance of endogenous lipid stores in comparison to limited CHO reserves.Diets high in fat upregulate the release, transport, uptake and utilisation of fat in the muscle, even in endurance athletes whose training would have been expected to maximise such adaptations (Spriet, 2014; Burke, 2015).

 

This concept has been explored in trained individuals in various formats over the past 40 years. Strategies have included chronic exposure to either a ketogenic (< 20 g day−1 CHO), high fat (80% of energy) diet (Phinney et al. 1983) or a restricted CHO (15–20% of energy), high fat (60–65% of energy) diet (Lambert et al. 1994; Goedecke et al. 1999) as well as short-term adaptation to a high fat diet and 1 day of high CHO availability (Burke et al. 2000, 2002; Carey et al. 2001; Havemann et al. 2006). Although these iterations of high(er) fat, low(er) CHO diets result in increased rates of fat oxidation during exercise of varying intensities, evidence that this substrate shift translates to a clear enhancement of sports performance in athletic populations is lacking (Burke&Kiens, 2006; Burke, 2015).

 

Despite this, there has been a resurgence of interest in the published literature and social media (Burke, 2015) in a specific application of the high fat diet for athletes; the chronic consumption of a very low (< 50 g day−1) CHO, moderate protein, high fat (75-80% of energy) diet. The dual intent of this strategy, termed LCHF or the ‘keto-diet’, is to increase the utilisation of fat as a muscle fuel and to expose the body to high levels of circulating ketones (Noakes et al. 2014; Volek et al 2015).

 

To date, the only published investigations of this diet in endurance athletes are a single intervention study (Phinney et al. 1983) and two recent cross-sectional studies comparing ultra-endurance runners/triathletes who have chosen this eating style with similar athletes following higher CHO diets (Volek et al. 2016; Webster et al. 2016). Since none of these investigations measured the effects of LCHF on sports performance or were undertaken using exercise of an intensity that is relevant to the majority of competitive endurance athletes, there is a need to systematically investigate claims that LCHF enhances endurance performance (Burke, 2015).

 

Accordingly, we determined the effects of a 3-week adaptation to an LCHF diet during a period of intensified training on exercise metabolism and performance of world-class endurance athletes. Comparisons of interest included both the traditional sports nutrition guidelines of training with sustained high CHO availability and the contemporary ideas around periodised CHO availability.

 

In conclusion, the results of the present study showed that despite achieving substantial increases in the capacity for fat oxidation during intense exercise, chronic adaptation to a ketogenic low-CHO, high fat diet impaired exercise economy and negated the transfer of training-induced increases in aerobic capacity into improved performance of a real-life endurance event in elite athletes. In contrast, training with a diet rich in carbohydrate and which provided either high or periodised carbohydrate availability around training sessions was associated with improved race outcomes

.  

 

Cf.  Re-Examining High-Fat Diets for Sports Performance: Did We Call the ‘Nail in the Coffin’ Too Soon?  (2015)

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4672014/

PMCID: PMC4672014

 

 

Mccoy: I'd also be interested to see the results on the military personnel. A keto diet would be invaluable since the commandos would be able to operate efficiently without food for days. Maybe it's classified...

 

It's certainly being looked into:

 

Journal of Special Operations Medicine   2017 Summer;17(2):112-116.

Ketones and Human Performance

https://www.ncbi.nlm.nih.gov/pubmed/28599043#

PMID:28599043

 

Abstract

Everyone is seeking nutritional strategies that might benefit performance. One approach receiving much attention is ketones, or ketosis. Ketones are very simple compounds made of hydrogen, carbon, and oxygen, and ketosis is a metabolic state whereby the body uses predominantly ketones. Ketosis can be achieved by fasting for longer than 72 hours or by following a very low carbohydrate, high-fat diet (ketogenic diet) for several days to weeks. Alternatively, ketone supplements purportedly induce ketosis rapidly and do not require strict adherence to any specific type of diet; however, much of the touted benefits are anecdotal.  A potential role for ketosis as a performance enhancer was first introduced in 1983 with the idea that chronic ketosis without caloric restriction could preserve submaximal exercise capability by sparing glycogen or conserving the limited carbohydrate stores.

 

Few human studies on the effects of a ketogenic diet on performance have yielded positive results, and most studies have yielded equivocal or null results, and a few negative results. Many questions about ketones relevant to Special Operations Forces (SOF) remain unanswered. At present, a ketogenic diet and/or a ketone supplement do not appear confer performance benefits for SOF. Instead, Operators should engage with their unit dietitian to develop individualized nutritional strategies based on unique mission requirements. The authors review the concept of a ketogenic diet, describe some potential benefits and risks of ketosis, review the performance literature and how to measure ketone status, and then summarize the landscape in 2017.

 

 

[mccoy]

I can't believe that phinney and colleaugues have been studying the keto diet since 1983. Considering the speed at which beneficial practices (beneficial to win the contest and not beneficial to health) are adopted in competitive sports environments, we must conclude there is little or no real practical beneficial effects so far, as the article underlines. Maybe they'll be able to find some optimal combination. 

[Todd Allen]

Stephen Phinney's work is getting more attention and races are being won

 

http://www.meandmydiabetes.com/2012/08/11/western-states-100-low-carber-wins-ultramarathon-steve-phinney-and-jeff-volek-study/

 

https://ultrarunning.com/features/interviews/zach-bitter-fastest-100-miler-in-us-history/

 

https://optimisingnutrition.com/tag/chris-froome/

[mccoy]

Thanks for the update Todd, at last the keto diet is yielding some results for some people to prove that theory can have application in real life (I was curious but had no hard facts on that). These are still isolated cases but probably, when there will be more guys practicing it, there are going to be more keto-winners. I remain scientifically curious about that.

 

Of course that remains a strictly specialized practice. We don't know about Thimoty Olson regimen, we only know it's been about 2000 kCAl instead of the usual 6000. It is not exactly as the theory predicts, that a runner can burn his/her own bodyfat for the whole duration of the contest. Yet a progress from the total dependence of huge loads of carbs (which, as told in the  article, can cause indigestion problems) occurred,

 

Also, Zach Bitter's regimen is pretty specialized and sometimes it appears like a mix between keto diet and carbs loading.

 

I consume plenty of fresh vegetables and fruits but do keep an eye on high glycemic fruits like bananas and pineapples. This diet is hardly depriving except that I am not having a ton of refined carbohydrates, which are nutritional wastelands relative to calves’ liver or broth or wild caught salmon. Because I am well fat-adapted and physically active, adding some carbs back into my diet doesn’t appear to have much of a negative impact.

 

 

Chris Froome apperently benefitted from the low carb diet because that caused a severe loss of weight. That I experienced myself.

[Todd Allen]

Tim Noakes is another example who wrote books on carb loading for running, became highly insulin resistant himself and then explored LCHF and now states all of his past work/advice was wrong and that LCHF is a superior approach for distance running.

 

Insulin impedes the ability to use fat (both endogenous and exogenous) as fuel.  LCHF and especially keto diets lower insulin facilitating fat burning.  The obvious benefit for endurance athletes is better access to their fat fuel tanks which even in super lean individuals contain vastly more energy than their stored carbohydrate.  But that's not the biggest factor as high carbohydrate athletes are allowed to sugar dope throughout most events.

 

It takes about 70% of the oxygen to produce an equivalent amount of ATP from fat as from sugar through oxidation.  Moving sufficient oxygen is a burden on the cardio-vascular system and as the balance of energy derived from fat increases the level of energy output at a given heart rate increases.  However, many sports entail peak power surges depending on fast twitch muscle producing power anaerobically and glucose is the only fuel for it.

 

The Tour de France with very dynamic power requirements has a bigger need for carbohydrate than sports like distance swimming or running.  So it isn't surprising that Chris Froome would still be consuming some carbs during the race.  But there is still advantage in achieving a higher balance of energy from fat throughout the race as that allows one greater sustained power output at max heart rate sparing the anaerobic muscle and it's glycogen stores for when it is most needed.  It also opens up the ability to get more of the in race carbs from slower and steadier resistant starch instead of sugar helping keep insulin lower and fat burning high.  There are a lot of factors to balance and master and I expect the interest in LCHF approaches to sports training will grow.

 

Finally, I suspect the issue you and your wife may have run into when low carb was insufficient electrolytes, in particular sodium.  If you read Phinney and Volek's books they explain how vital they have found it for low carb athletes to massively increase their intake of salts.  Following their guidance I doubled my intake from roughly 1.5 grams to 3 grams of sodium per day as well as modest supplementation of potassium, magnesium and calcium.  I recently read the new book "the salt fix" which goes far more into the science of salt.  And I came to realize that 3 grams of added sodium daily is not nearly enough for my combination of diet and regimen.  A few days ago I began increasing sodium further, now I'm at about 6 grams/daily and everything is getting better, heart rate, blood pressure, hrv,  blood glucose is dropping, ketones are up, appetite is coming down and weight is dropping again and I'm again making daily increases in physical performance.

[Sibiriak]

Todd Allen:  It takes about 70% of the oxygen to produce an equivalent amount of ATP from fat as from sugar through oxidation

 

Cf. Dan Benardot,  Advanced Sports Nutrition  ( Second Edition ):

 

Carbohydrate is a critical fuel for athletes because we can more efficiently create energy per unit of oxygen from carbohydrate than from any other fuel. One liter of oxygen can yield approximately 5 calories from carbohydrate but only 4.7 calories from fat. In addition, aerobic glycolysis can produce ATP for muscular work in a larger quantity and at a faster rate than the oxidation of fat can produce it. 

 

 

[Sibiriak]

High Fat Diet and Endurance Exercise Performance

Sports Performance pp 151-156  (2015)

https://link.springer.com/chapter/10.1007/978-4-431-55315-1_13

 

Abstract

The high carbohydrate diet has been a popular dietary intervention among endurance athletes for many years, because the depletion of muscle glycogen is associated with fatigue during endurance exercise. Therefore, numerous studies regarding carbohydrate supplementation and exercise regimens have been done and have demonstrated the association between muscle glycogen and performance in endurance exercise. These results strongly suggest the importance of maximizing muscle glycogen stores before the initiation of exercise to allow the athlete to have an optimal endurance performance. On the other hand, high fat diet intervention is not popular, although it has been reported that a high fat diet induces an increase in mitochondrial biogenesis in skeletal muscle and enhances endurance performance in animal studies. Therefore, the purpose of this article is to consider the evidence that an increased in fat intake is beneficial for endurance performance.

 

 

Full text here:

http://extras.springer.com/2015/978-4-431-56299-3/978-4-431-56299-3_Book_PrintPDF.pdf

 

 

[Todd Allen]

Oops, Sibiriak you are right.  I had oxygen consumption confused with figures on RQ or respiratory quotient.  The RQ for fat metabolism is 0.7 compared to 1.0 for carbs.  RQ is the ratio of CO2 produced for oxygen consumed and fat produces less CO2 for the oxygen consumed not what I was stating of less oxygen being consumed.