Monthly Archives: March 2011

A Cure for Migraines?:

The weekend was happy for us, because a number of readers left word of health improvements.

Raynaud’s Syndrome, Constipation, and Other Problems Relieved

Becky reported that her Raynaud’s was better:

Hat tip and thank you: After I started reading your blog, and adding in “safe starches”, my Reynaud’s largely cleared up with temperatures over 20F. This wasn’t the intention, but a wonderful side-effect. Last month, when the sun came out and the temps got over 25, I enjoyed a successful 2-mile snow hike for the first time in three years. =)

Kate reported the same:

I too have had Raynaud’s all my life … In the past two months, I have modified my diet in line with Paul’s suggestions for Migraine. I now eat 200 calories worth of safe starch, all the recommended supplements, and as much coconut oil as I can stomach. I am also doing the 16/8 fast. My Raynaud’s has further improved, as measured by the fact I sometimes forget to turn the heat up in the morning, and cold extremities don’t always alert me to my forgetfulness!

Bill, who last October reported a variety of health complaints which persisted after he adopted a Primal Diet in May 2009, has experienced a big improvement:

I definitely feel 100% better with a more appropriate caloric intake and some starch.

Betty reported her constipation was gone:

You have blessed my life. I had one final symptom that was chronic all my life. Constipation. I e-mailed you last week and you offered up some suggestions. PRAISE THE LORD! I have had NO IBS, or constipation since following your advice. I am, and will be forever grateful.

I’ll discuss my constipation advice in Thursday’s post. Today I want to discuss migraines.

Migraines

You may recall that reader Rob Sacks cured his migraines through ketogenic dieting. I asked Kate if her migraines had responded. Here was her reply:

Thanks for asking about the Migraines. They are in fact vastly improved, which I attribute solely to your recommendations. I can say that, because I have tried virtually everything else in the past.

Kate sent me a full account of her experiences by email. It is fascinating and she has given me permission to share it. The next section was written entirely by Kate.

Kate’s Story

Thanks for asking about the migraines.  They are in fact vastly improved!  Since they have been so intractable in the past, I guess I was waiting to make sure the effect was stable before I reported my results. But clearly something remarkable is happening, thanks to your recommendations!

A little history.  I started getting these headaches in my late 30s.  (I am now 52).  In the beginning I thought I had the stomach flu, because in addition to the headache I would always throw up or have dry heaves.  The worst headaches would keep me immobilized in bed for up to two days.  My brother-in-law, a neurologist, convinced me they were migraines. I finally consulted a doctor, who put me on midrin, which did not help, and a few months later I started on imitrex, which did help, at least at first.  Eventually, my headache pattern evolved, and I had at least a mild headache every day, punctuated by the occasional doozy.  Apparently, this is a pretty common progression, especially with women my age.  I always suspected there was something wrong with my lifestyle or diet, and over the years I have tried numerous experiments, but nothing ever worked.  Here is a summary of what I have tried, more or less in order. Unless noted, these were all for three months.

What I tried The inspiration The results
Chelated Magnesium and riboflavin Mauskop’s book What Your Doctor May Not Tell Your about Migraines nada
Expensive German butterbur preparation Magnum website (www.migraine.org) nada
Forever Well Gut Brain Therapy (a mix of probiotics, peptides, and a state of the art supplement to support the organs of elimination) Magnum website I think I slept a little better.  No help with headaches.  Was surprised that the president of the company called me to see if the supplements were helping
Amitriptyline, a tricyclic anti depressant—my first foray into pharmaceutical prophylactics My doctor insisted I consult a neurologist Tried for 4 months. Slept like a zombie, and acted like one.  No help with headaches.
45 minutes of low intensity aerobics 6 days a week Inspired by Crowley and Lodge’s Younger Next Year—Never mind I had been exercising regularly all my life. Got a heart rate monitor and got after it.  No help for headaches.
No caffeine, alcohol, triptans, or over the counter analgesics Buchholz  Heal Your Headache. I love my coffee, so this was a big step for me. Did this for four months.  Very sleepy for first few days.  Did NOT help with headaches.  However, I felt I could rule out medicine overuse headaches.
Cerapamil—A calcium channel blocker My primary care manager thought it would be worth a try. Tried for four months, and upped dose after a few weeks.  Extreme constipation and painful cramps.  No help with headaches.
Low carb diet Found a reference to a german website of someone who had cured his headaches with a low carb diet.  I had always though low carb diets were ridiculous, but decided to give it a try Immediate improvement within a few days!  Also cured insomnia and acid stomach within a week. Headaches were less severe by about 50%.  Frequency was unchanged however.  Remained on low carb diet and manipulated the variables, but did not find further headache improvement.
Vitex Always felt there was a hormonal connection nada
Natural progesterone cream Same Didn’t help my headaches, but did weird things to my period
Nortriptyline–another tricyclic antidepressant My brother-in-law, a neurologist thought I should try it. Did seem to help a little.  Had to stop in less than a month because it gave me high blood pressure.
Birth Control-Yaz PCM sent me to gynecologist for heavy menstrual bleeding.  Benign fibroids found.  Doc was sure Yaz (without placebo pills) would help heavy bleeding and headaches.  I didn’t care about the bleeding, but I rose to the headache relief bait. Tried for five months. Spotted every day, but got no headache relief.
Inderal-a beta blocker Neurologist Seemed to help, but my blood pressure went too low.
Fish oil, vitamin D, coenzyme Q10, and various other supplements Grasping at straws Tried these at various times. No noticeable effects
Acupuncture same No noticeable effects, but I didn’t really believe
Self analysis, meditation Sarno The Mind Body Prescription I think there is something to this, but no headache relief for me.  Do feel more at peace with myself.
Topamax-epilepsy drug Neurologist Low dose did not help.  Worked up to 100mg over four months. Did not help headaches.  Gave me extreme anxiety about driving on limited access roads.  I didn’t notice the connection, but my college age daughter did.  I immediately tapered off.

Got off the Topamax last summer, and forswore further pharmaceutical prophylactics at that point.  In the meantime I stumbled upon the profusion of “primal” material that is now out.  I had not read any low carb stuff for a couple years, and I enjoyed reading Sisson, Wolf, Cordain, et al.  I started eating more saturated fat. I also read Fallon’s Nourishing Traditions, and started eating liver again, which I had loved as a child.  Her book inspired me to order some kelp tablets for iodine, and I took one here and there when I thought of it.  In January, in my blog travels, I stumbled on your site.  I ordered the book and was intrigued by your and Shou-Ching’s ideas about disease and chronic conditions.  I was already familiar with the idea of a ketogenic diet for epilepsy, so I was immediately interested in trying a more ketogenic diet for myself.

I ordered all your basic supplements, and immediately upped my kelp to two capsules.  I had been using coconut oil for curries, so I started using it habitually.  Started eating 200 calories of starches that you recommended—this was a little scary, after studiously avoiding them for four years!  I was afraid I they might keep me awake at night, but I am sleeping like a log. Started fasting 16/8, which was easy once you absolved me for having cream in my morning coffee!

Within a week of starting this regimen my chronic headache started to disappear! Some days I would only have a headache for part of the day, and occasionally I would have no headache at all!  I read somewhere on your site that NAC is good on a ketogenic diet, so I ordered it too.  I had never heard of this supplement before.  It seems to have made a further positive difference.  I have started taking it twice a day.  Once before bed, and once in the late afternoon, when the headache sometimes starts coming back.  Since I added NAC, I have been nearly headache free.

Another amazing development concerns anxiety.  Over the years I have become somewhat anxious when I drive on highways. I grip the steering wheel tightly, sit forward in the seat, and am generally hyper vigilant. I always chided myself for my lack of nerves, but that didn’t help.  As mentioned above, this was magnified by the Topomax.  I never had this issue when I was younger; indeed I used to fly helicopters in the army.  Two weeks ago I drove up to New Jersey to pick up my daughter, a 3.5 hour trip from where I live in Northern Virginia.  I stopped two hours into the trip to make a pit stop, and I suddenly realized I was totally relaxed, and had been for the entire trip!  The PHD is strong brain medicine indeed!

Thanks for all your research, insights, and ideas.  I think the Perfect Health Diet is going to be a game changer for many people.  Hopefully it is the start of a sea change at how we approach the chronic maladies of our times.

Mechanisms

Thank you, Kate! That’s a fantastic chronicle of your history.

This is already a long blog post, so I won’t go into an analysis of why and how the ketogenic variant of the Perfect Health Diet can cure migraines, reduce anxiety, and improve sleep. I’ll only add a few things.

First, there is a case report in the literature of a ketogenic diet helping migraines. [1]

Second, the diet helps in part by getting around mitochondrial dysfunction. Some other nutritional supplements that support mitochondrial function have a chance to help:

  • carnitine [2]
  • riboflavin [3,5]
  • CoQ10 [4,5]
  • alpha lipoic acid [4]
  • magnesium [4, 5]

I realize that you’ve already tried those, Kate, and didn’t notice an effect, but you may notice a benefit now that your diet is better. If in the past they reduced headache severity from 100% to 99%, you wouldn’t have noticed a change. If now they reduce severity from 2% to 1%, or 1% to 0%, the improvement might be obvious. So you might re-consider them now.

Finally, in the interests of full disclosure I should note that some doctors expect improvements from diet and nutrition to be short-lived: “high-dose vitamin and cofactor treatment and, where applicable, high-fat diet, are well tolerated and possibly effective in the short term, but ineffective in the longer term” against mitochondrial disorders. [6]

I believe that fading benefits are likely a result of eating the wrong diet, and that on the ketogenic version of the Perfect Health Diet the good effects will prove permanent. But time will tell.

Conclusion

We believe that diseases are generally caused by food toxins, malnutrition, and pathogens. The Four Steps of the Perfect Health Diet eliminate food toxins, optimize nutrition, and enhance immunity; therefore they remove most of the causes of disease and should render most diseases curable.

But we had no idea, last October when our book was released, which cures would appear first.

It’s interesting that migraines are appearing so early as a curable disease. I think this says a lot about the discipline, and eagerness for a cure, of Rob and Kate. Rob was willing to fast for 30 days (!); Kate read the book in January and was able immediately to make substantial diet, lifestyle, and supplement changes.

It seems that a painful but non-debilitating disease will create the most dedicated, venturesome patients.

I’m very grateful to Kate for trying the diet and sharing her story. Hopefully we can bring the good news to others, and gather more evidence to prove that diet is the best therapy – for migraines, and for many other diseases as well.

References

[1] Strahlman RS. Can ketosis help migraine sufferers? A case report. Headache. 2006 Jan;46(1):182. http://pmid.us/16412174.

[2] Kabbouche MA et al. Carnitine palmityltransferase II (CPT2) deficiency and migraine headache: two case reports. Headache. 2003 May;43(5):490-5. http://pmid.us/12752755.

[3] Triggs WJ et al. Neuropsychiatric manifestations of defect in mitochondrial beta oxidation response to riboflavin. J Neurol Neurosurg Psychiatry. 1992 Mar;55(3):209-11. http://pmid.us/1564483.

[4] Sun-Edelstein C, Mauskop A. Foods and supplements in the management of migraine headaches. Clin J Pain. 2009 Jun;25(5):446-52. http://pmid.us/19454881.

[5] Taylor FR. Nutraceuticals and headache: the biological basis. Headache. 2011 Mar;51(3):484-501. http://pmid.us/21352223.

[6] Panetta J et al. Effect of high-dose vitamins, coenzyme Q and high-fat diet in paediatric patients with mitochondrial diseases. J Inherit Metab Dis. 2004;27(4):487-98. http://pmid.us/15303006.

Pesto

Pesto is a classic Italian sauce that originated in Genoa. The traditional ingredients are basil, crushed garlic, grated parmigiano or pecorino cheese, pine nuts, and olive oil.

It’s traditionally prepared with a mortar and pestle (thus the name), but we use a food processor. We also vary the ingredients from time to time.

The nice thing about pesto is its versatility: it can flavor a lot of Perfect Health Diet foods. Like a good poet, pesto makes the familiar new.

Pesto with Rice Cakes and Shrimp

Here are the ingredients for a traditional pesto: grated cheese, pine nuts, garlic, olive oil, and basil.

Pine nuts will usually taste better toasted. You can buy them pre-roasted, but if you buy raw pine nuts it’s not hard to toast them yourself. Heat a dry pan, then turn the heat off and add the pine nuts. Stir until done. Careful, they can burn quickly.

The basil takes up too much space for our food processor, so we put the basil and garlic in first for pre-shredding:

Then add the other dry ingredients, with some pepper:

Mix, adding olive oil to the food processor until it has the desired consistency. The finished product:

The sauce is now ready. Here we put it on some rice cakes and shrimp. Rice cakes are usually found in the frozen foods section of Asian supermarkets. Look for rice cakes that have no wheat (which is sometimes added to help the cakes stick together). Remember that rice cakes cook very quickly – 1 to 2 minutes in boiling water. When they float, they’re done; be sure to quench them in cold water to stop them from overcooking.

Spreading the sauce:

Ready to eat:

Macadamia Pesto with Buttered Potato or Liver

This one is similar but we used macadamia nuts in place of pine nuts, and included a bit of lemon juice. Macadamia nuts are lower in omega-6 than pine nuts:

Here it is in the food processor with most of the oil in:

Here it is with boiled potatoes and butter, for a sort of pesto potato salad:

Here it is with boiled liver:

Boiling liver removes a lot of the flavor, and adding substantial amounts of a pesto may make it palatable to those who dislike the taste of liver.

Conclusion

Any traditional food can be made Perfect Health Diet-compliant by swapping out ingredients. Pesto is pretty healthy to begin with, but replacing pine nuts with a low-omega-6 nut can make it even better.

Staple foods like rice, potatoes, and beef liver can get tiresome if they’re always eaten the same way. Luckily, traditional cookbooks are full of good sauces that vary the flavor of familiar foods. Be a poet in the kitchen, and look for flavors that can make the new familiar and the familiar new.

Around the Web; and What is the Antidote to Stress?

Here are things that caught my eye this week:

[1] Oxygen Bad, Carbon Dioxide Good?: Gary Taubes told us there were good calories, bad calories; now the New York Times tells us of good air, bad air.  The Buteyko method, a shallow-breathing technique developed in 1952 by a Russian doctor, Konstantin Buteyko, can greatly improve asthma. The explanation:

Mrs. Yakovlev-Fredricksen said: “People don’t realize that too much air can be harmful to health. Almost every asthmatic breathes through his mouth and takes deep, forceful inhalations that trigger a bronchospasm,” the hallmark of asthma.

“We teach them to inhale through the nose, even when they speak and when they sleep, so they don’t lose too much carbon dioxide,” she added.

I find it’s a challenge to keep my mouth closed, so I guess I must be deficient in carbon dioxide!

[2] Gary Taubes should use this: Yes, it is possible to be a 405-pound marathoner.

[3] Interesting posts this week: Emily Deans draws some lessons for healthy weight loss from the Ancel Keys experiments. Dennis Mangan lists a number of papers showing that the elderly live longer when their serum cholesterol is higher. (See also O Primitivo.) CarbSane sets forth her Credo. Beth Mazur comes up with a great scheme for judging the healthfulness of food: Weight Maven’s EZ Points scheme. Julianne Taylor reports that good things happen when pets eat their wild diets.

Finally, Paleo vs non-Paleo:

[4] Comment of the week: Michelle reports that Raynaud’s syndrome might be an infectious condition – and shares the good news that her arthritis is improving with antibiotic therapy:

Dr. Thomas McPherson Brown considered Raynaud’s to be in the family of rheumatoid diseases, and found it responded well to low dose pulsing tetracyclines.  Those pesky stealth infections!

http://en.wikipedia.org/wiki/Thomas_McPherson_Brown

http://www.roadback.org/index.cfm/fuseaction/studies.display/display_id/96.html

Michelle, on low dose pulsing Doxy for Rheumatoid Arthritis and doing well.

[5] Don’t forget to exercise: From a recent review:

Several large cohort studies have attempted to quantify the protective effect of physical activity on cardiovascular and all cause mortality. Nocon et al. in a meta-analysis of 33 studies with 883,372 participants reported significant risk reductions for physically active participants. All-cause mortality was reduced by 33%

Reference: Golbidi S, Laher I. Molecular mechanisms in exercise-induced cardioprotection. Cardiol Res Pract. 2011 Mar 6;2011:972807. http://pmid.us/21403846.

(Via Fight Aging!)

[6] Animal photo: Are these two married?

[7] Medical Breakthrough from Bangladesh: From Foreign Policy, how a civil war ended cholera.

[8] It’s Dad’s fault: When obese, insulin-resistant, low-testosterone male mice were bred with lean, healthy females, their daughters had diabetes-like pancreatic beta-cell dysfunction. They inherited the condition from their fathers via epigenetically modified sperm.

This supports other evidence that obesity induces hard-to-reverse changes throughout the body, and that these changes can be passed on epigenetically.

In an evaluation at F1000, one of the reviewers wondered if low testosterone might be the key. It turns out that men with low testosterone are more likely to develop pancreatic beta-cell dysfunction. Perhaps low testosterone causes diabetes in men and their daughters.

Meanwhile, Sean at PaleoHacks found a psychology paper asserting that “displays of power” increase testosterone. Might this be a new, annoying cure for diabetes?

References:

Ng SF et al. Chronic high-fat diet in fathers programs ?-cell dysfunction in female rat offspring. Nature. 2010 Oct 21;467(7318):963-6. http://pmid.us/20962845.

Stellato RK et al. Testosterone, sex hormone-binding globulin, and the development of type 2 diabetes in middle-aged men: prospective results from the Massachusetts male aging study. Diabetes Care. 2000 Apr;23(4):490-4. http://pmid.us/10857940.

(via The Scientist)

[9] No, it’s Mom’s fault: Mice born to obese mothers are more likely to be infertile (source).

Reference: Martin JR et al. Maternal Ghrelin Deficiency Compromises Reproduction in Female Progeny through Altered Uterine Developmental Programming. Endocrinology. 2011 Feb 15. [Epub ahead of print] http://pmid.us/21325042.

[10] Turkeys at Harvard Medical School: No, I don’t mean the doctors. These turkeys:

Via Mike the Mad Biologist.

[11] Declining health since 1998: Via J. Stanton at gnolls.org, lifespan isn’t correlated with health, and health may have peaked in 1998. Our lifespans are still lengthening, but our “healthspans” are shortening. Women can expect to be unable to walk up stairs for the last 10 years of their lives:

[A] 20-year-old today can expect to live one less healthy year over his or her lifespan than a 20-year-old a decade ago, even though life expectancy has grown….

A male 20-year-old today can expect to spend 5.8 years over the rest of his life without basic mobility, compared to 3.8 years a decade ago — an additional two years unable to walk up ten steps or sit for two hours. A female 20-year-old can expect 9.8 years without mobility, compared to 7.3 years a decade ago. (source)

I’m shocked at the magnitude of the health impairments people will live with, but not surprised by the trend. It’s a natural consequence of rising consumption of toxic industrially processed foods.

Our book discusses evidence from Pottenger’s Cats, famine studies, and the Flynn effect that toxicity and malnutrition have transgenerational effects. If diets don’t improve, we might expect the biological damage to be fully visible in the third generation born after toxic food consumption rose in the 1970s.

Reference: Crimmins EM, Beltrán-Sánchez H. Mortality and morbidity trends: is there compression of morbidity? J Gerontol B Psychol Sci Soc Sci. 2011 Jan;66(1):75-86. http://pmid.us/21135070.

[12] Quote of the week: Charles De Montesquieu: “Lunch kills half of Paris, supper the other half.” If they’d had sugary cereals in those days, breakfast would have gotten the third half!

[13] Elizabeth Taylor died this week at 79. Not enough fat and micronutrients in her diet (indicated by osteoporosis, five vertebral fractures, and two hip replacements); too many cigarettes and other toxins (likely contributors, along with nutrient deficiencies, to her congestive heart failure); too many husbands and, to cover up the damage, too much make-up. But there was never a more beautiful girl:

[14] Stress is Bad – Mythically Bad: Some good things on stress this week. First, Chris Kresser concludes his “9 Steps to Perfect Health” series with advice to “Practice Pleasure”. Pleasure, Chris explains, is “the antidote to chronic stress.”

What’s so bad about stress? A study of 17,000 adults in Stockholm, Sweden found that those with mild psychological stress were more likely to become disabled:

Even mild psychological distress was independently associated with the award of a disability pension … Mild psychological distress may be associated with more long-term disability than previously acknowledged and its public health importance may be underestimated. (source)

Reference: Rai D et al. Psychological distress and risk of long-term disability: population-based longitudinal study. J Epidemiol Community Health. 2011 Mar 21. [Epub ahead of print] http://pmid.us/21422028. (Via Russ Farris)

Finally, I enjoyed an excerpt from The Myth of Stress: Where Stress Really Comes From and How to Live a Happier and Healthier Life by Andrew Bernstein.

I was intrigued by the emphasis Andrew places on psychological stress, since I tend to assume that chronic stress is a symptom of some underlying physical ailment. Andrew argues that psychological stress is important in its own right, and that it is remediable:  “the more insights you have … the less you experience stress.”

Even more interesting was Andrew’s critique of stress pioneer Hans Selye, based on later experiments done by Dr. John W. Mason. Andrew concludes:

There is no such thing as a stressor. Nothing has the inherent power to cause stress in you. Things happen (divorce, layoffs, disease, etc.), and you experience stress – or you don’t – depending on what you think about those things. Stress is a function of beliefs, not circumstances.

I believe disease and infections can cause stress in even the most resilient and insightful people, but I’m also willing to believe the psychological aspects of stress are very important. Why did Viktor Frankl survive Auschwitz? Surely insight was part of it.

Reading the excerpt was both pleasurable and insight-generating, so I’m expecting the full book to be a great stress-reducer!

[15] Why the Neandertals went extinct:

French paleontologists have discovered a Neanderthal cave painting said to represent hands eagerly reaching for a Big Mac, or at least proto-Big Mac, according to the journal, Ancient Discoveries….

“What is most striking about this painting,” says Bouisquet, “is that this is precisely the time period during which Neanderthals went extinct. One naturally wonders, Could the consumption of fast food have contributed to the extinction? As yet we simply don’t know.”

From Glossy News, via John Hawks.

[16] Video of the week: The sky of the Mayas.  Tikal was the capital of one of the most powerful Mayan kingdoms. It is now part of Guatemala’s Tikal National Park and is a UNESCO World Heritage Site.

The soundtrack is a recording of Howler monkeys. The video was made by Stéphane Guisard. Enjoy:

Why Did We Evolve a Taste for Sweetness?

After I did my post on Seth Roberts’s new therapies for circadian rhythm disorders, Seth learned of my experience with scurvy and blogged about a similar experience of his own.

Seth made the important point that food cravings are driven by nutritional deficiencies – a point I heartily agree with, which is why it’s so important for those seeking to lose weight to be well nourished – and asked, “Why do we like sweet foods?” His suggested answer was that the taste for sweetness encouraged Paleo man “to eat more fruit so that we will get enough Vitamin C.”

This led to a fascinating contribution from Tomas in the comment thread:

I have read several books on the Traditional Chinese Medicine and they attributed that increased craving for sweets is in fact signaling some serious nutritious deficiencies. They said that it’s in fact meat or starches or other nutritionally dense foods that will soothe the craving, but sweets are more readily available. The taste of meat is in fact sweet as well.

In my experience this seems (the TCM view) to be true. I always have been very skinny, but eating enormous amounts of sweets. After I switched to a proper, paleo-like diet, the situation changed in many aspects and I no longer have such strong cravings and slowly I am gaining some weight.

Shou-Ching and I have great respect for the empirical claims of Traditional Chinese Medicine, and so I found this a fascinating idea. Is our modern taste for sweets actually derived from a taste that evolved to encourage meat eating?

Human tastes

It is generally agreed that animals evolved the sense of taste to detect nutrients and toxins:

Taste helps animals to decide whether a food is beneficial for them and should be consumed or whether it is dangerous for them and should be rejected. Probably, taste evolved to insure animals choose food appropriate for body needs. [1]

The five basic human tastes are sweet, salty, sour, bitter, and umami. Each taste detects either a nutrient class we need or toxins we should avoid:

  • Sweet – carbohydrate.
  • Salty – electrolytes.
  • Sour – acids.
  • Bitter – toxins.
  • Umami – glutamate and nucleotides.

Electrolytes are essential to life, and toxins best avoided, so the evolution of salty and bitter tastes is easy to understand. The umami taste is mainly a sensor for natural (healthy) protein. The sour taste is interesting, in that it is attractive in small doses but aversive in large. Seth argues that low-dose sourness is desirable because it leads us to seek out fermented foods, which supply probiotic bacteria and their fermentation products such as vitamin K2. If so, it is natural that strong sourness, indicating high bacterial populations, would be aversive.

But what of the sweet taste? Is it really a sensor for carbohydrates? If so it does a rather poor job. The healthiest carbohydrate source – starch, which is fructose-free – hardly activates this taste, while fructose, a toxin, activates it in spades. If this taste evolved to be a carbohydrate sensor, it should have made us aversive to the carbohydrates it detects, as the bitter taste makes us avoid toxins. But sweet tastes are attractive!

Sweetness activators

It turns out that the sweetness receptors are complex; many things activate them, and they appear to serve multiple functions.

Wikipedia (“Sweetness”) notes:

A great diversity of chemical compounds, such as aldehydes and ketones, are sweet.

Some of the amino acids are mildly sweet: alanine, glycine, and serine are the sweetest. Some other amino acids are perceived as both sweet and bitter.

The sweetness of some amino acids would seem to support Tomas’s assertions that sweetness detect meat: perhaps it is detecting amino acids. But this seems a bit odd: there is another taste, umami, that detects protein. Would we really need two taste receptors for protein? And lean meats don’t taste sweet.

A possible clue is that the sweet tasting amino acids are hydrophobic, while hydrophilic (or polar) amino acids are not sweet.

Proteins that are hydrophobic end up lodging in cell membranes alongside lipids; proteins that are hydrophilic dissolve in water and reside apart from the fat. Glutamate and nucleotides, which are detected by the umami taste, are hydrophilic and water-soluble.

So maybe the umami taste detects proteins that aren’t associated with fat, while the sweet taste detects proteins that are associated with fat.

Indeed, a leading theories of sweetness holds that compounds must be hydrophobic, or fat-associated, in order to invoke the sweetness taste:

B-X theory proposed by Lemont Kier in 1972. While previous researchers had noted that among some groups of compounds, there seemed to be a correlation between hydrophobicity and sweetness, this theory formalized these observations by proposing that to be sweet, a compound must have a third binding site (labeled X) that could interact with a hydrophobic site on the sweetness receptor via London dispersion forces. Wikipedia (“Sweetness”)

The sweet taste seems to work in collaboration with the bitter taste to regulate toxin avoidance. Wikipedia (“Sweetness”) again:

Sweetness appears to have the highest taste recognition threshold, being detectable at around 1 part in 200 of sucrose in solution. By comparison, bitterness appears to have the lowest detection threshold, at about 1 part in 2 million for quinine in solution.[4] In the natural settings that human primate ancestors evolved in, sweetness intensity should indicate energy density, while bitterness tends to indicate toxicity[5][6][7] The high sweetness detection threshold and low bitterness detection threshold would have predisposed our primate ancestors to seek out sweet-tasting (and energy-dense) foods and avoid bitter-tasting foods. Even amongst leaf-eating primates, there is a tendency to prefer immature leaves, which tend to be higher in protein and lower in fibre and poisons than mature leaves.[8]

This makes some sense: we need a certain number of calories per day, and since “the dose makes the poison,” what determines the toxicity of the diet as a whole is not the amount of toxins in a food, but the ratio of toxins to calories. In an evolutionary setting, our ancestors needed to eat foods with a low toxin-to-calorie ratio in order to minimize daily toxin intake.

So if sweetness is an “energy density” detector, it should be especially strongly activated by fatty foods. If it detects fat-associated compounds, then it would do so.

Why not detect fats directly? In natural foods, fats are bound in triglycerides or phospholipids which are chemically inert. So they won’t bond to taste receptors. Free fatty acids will, but these are not present in fresh foods and would probably indicate some kind of degradation of the food. In fact there seems to be a taste receptor for free fatty acids, CD36 [2], but this may be an aversive sensor for decayed food.

Interestingly, color also affects sweetness:

The color of food can affect sweetness perception. Adding more red color to a drink increases its sweetness with darker colored solutions being rated 2–10% higher than lighter ones even though it had 1% less sucrose concentration.[26] Wikipedia (“Sweetness”)

So red meats are sweetest. Richard Nikoley would approve.

Summary and A Puzzle

A plausible inference would be:

1.      The sweet taste evolved primarily to encourage the eating of fatty, energy-dense meats; and of essential fat-associated micronutrients such as choline and inositol.

2.      The sweetness of fruit may result from plants having evolved a way to hijack the sweetness receptors, and animal food preferences, for their own purposes.

This still leaves a few puzzles. Why, Seth asks, do we tend to neglect sweet tastes when we are hungry, but after dinner is done crave sweet desserts?

Here’s something to consider. Fats are a special macronutrient. We have unlimited storage space for fats, in our adipose tissue, but very limited storage space for other calories. Once we’re full, of course we should lose our appetite for calories we cannot store. But for fats, why not get a little extra in case food is scarce in days to come? There’s always room for a little more fat.

Implications for Binge Eaters

Correct me if I’m wrong, but when people go on an eating binge, they go for sweets.

Presumably, they have a craving for the sweet taste – which, evolutionarily, may be a craving for fatty meats and fat-associated micronutrients.

But if they’ve imbibed the anti-fat propaganda of recent decades and are afraid to eat fat, binge eaters must follow their taste buds to sugars – which unfortunately fail to satisfy any of the micronutrient deficiencies the sweet craving is designed to redress.

Perhaps, then, a good fatty steak, preferably accompanied by some liver and cream sauce, would be the best cure for binge eating. It would satisfy the craving, but also satisfy the underlying nutritional need that generated the craving.

Implications for Weight Loss

If, as I believe, the key to weight loss and curing obesity is eliminating appetite, then it’s important to eliminate any deficiencies of fat-associated micronutrients. Micronutrient deficiencies trigger food cravings, and deficiencies of fat-associated micronutrients will trigger a craving for sweets.

In the modern world, we know how a craving for sweets is likely to be satisfied – by eating sugary, nutrient-poor foods. Unfortunately these foods do not contain the fat-associated nutrients (such as choline) whose deficiency is probably driving the craving. So the craving persists unabated no matter how many sugars are eaten.

Persistent food cravings despite an excess of caloric intake is probably a necessary (though not sufficient) condition for obesity to develop. Unsatisfied cravings probably make weight loss extremely difficult.

What of Vitamin C?

Vitamin C – ascorbic acid – is an acid so it directly activates the sour taste.

So perhaps the sour taste evolved to help us get vitamin C. This would actually complement Seth’s idea that the sour taste encourages us to eat fermented foods. Fermented foods are high in vitamin C.

I had a fairly severe case of scurvy and don’t recall being attracted to sweet flavors. Instead, I was ravenously hungry. My appetite generally, not craving for any particular taste, was promoted. If anything, I was less attracted to sweet tastes. So I think it’s plausible that vitamin C deficiencies may lead to a general appetite upregulation, or to cravings for sour foods, rather than a craving for sweets.

Conclusion

Our evolved taste receptors can tell us a lot about what our bodies need. Food cravings are a pretty good sign of an unsatisfied nutrient deficiency.

But sometimes, it’s less than obvious what a craving signifies. Our modern food environment is so different from the Paleolithic: We have many industrially produced foods designed to fool our Paleolithic taste buds into eating nutritionally unsatisfying calories.

Humans evolved, not in the forests where fruit was available, but in open woodlands where tubers and other tasteless starch sources were abundant but fruit rare. In this context, our cravings for sweet foods may have been directing us to eat animal fats.

It may be that the cravings for sweets often experienced by binge eaters and the obese are really a craving for animal fats. If you feel drawn to sugar, perhaps you should ask yourself: Steak or salmon?

References

[1] Bachmanov AA, Beauchamp GK. Taste receptor genes. Annu Rev Nutr. 2007;27:389-414. http://pmid.us/17444812.

[2] Laugerette F et al. CD36 involvement in orosensory detection of dietary lipids, spontaneous fat preference, and digestive secretions. J Clin Invest. 2005 Nov;115(11):3177-84. http://pmid.us/16276419.

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