RSS Feed

Tag Archives: science

Paleo Perspective on Vaccinations and a Refutation of Dr. Mercola’s Article

Posted on
vaccine

Today Dr. Mercola posted an article called, “Don’t Give This to Your Daughter – Despite What Your Doctor Says.” When I saw his article in my newsfeed, I immediately read it. While interesting, several of his points are somewhat inaccurate and misrepresent the true evidence. Vaccination is a contentious issue, and it’s important to understand the scientific literature out there. Please do not jump to conclusions based simply on the timing of onset of health issues. The Paleo community sometimes has a tendency to place too much faith in the philosophy that living like a caveman means rejecting accepted medical wisdom. Take a step back and consider the evidence:

1. Adverse Events:

Dr. Mercola cites the 23,000 Gardasil-related adverse events in the Vaccine Adverse Events Reporting System (VAERS), a website database with unverified reports of adverse events. Any individual can go on this website and report a supposed negative side effect of the drug. Here’s how this works: remember when people thought Autism Spectrum Disorders resulted from the childhood MMR vaccine? Well, this fact has been 100% proven to be false, with the initial study completely discredited. I won’t get into that here, but my point is, people jump to conclusions rather easily when their children’s health is at stake. Fainting has been associated to a small extent with the vaccination, as has minor infection, but “no serious adverse effects occurred” in a 60-day follow-up study published in the journal Archives of Pediatrics and Adolescent Medicine (http://www.landesbioscience.com/journals/vaccines/ 2012HV0811N.pdf). I could go on and on with study after study NOT funded by industry, but it would be a waste of all of our time. Here’s the real data: True scientific literature all reports that side effects associated with Gardasil are mild (http://www.ncbi.nlm.nih.gov/pubmed/19283255). When the events that are self-reported on the above website are analyzed by independent researchers, they are largely found to be unrelated to the vaccination in question.

2. Claim That Infection Is Not Harmful:

Dr. Mercola says that “As a vaccine for children, it doesn’t make sense to vaccinate to try to prevent an infection that is cleared from your body without any negative effects within two years in most healthy persons.” Now, he is completely right that education is one of the most important aspects of prevention, which we all believe is key in medicine. No one is disagreeing that many people are infected with HPV at some point in their lives. In fact, 50% of sexually active individuals will contract it at some point in their lives (http://www.cdc.gov/std/HPV/STDFact-HPV.htm). The problem is not HPV itself, although genital warts sound pretty unpleasant, but the fact that almost all cervical cancer is HPV-related. Cervical cancer is the third most common cancer worldwide, and 80% of cases occur in the developing world, where it causes hundreds of thousands of preventable deaths each year. Remember, vaccination is not only about individual protection. We need to think of individuals outside of the US and associated developed countries, where sexual education is infinitely better than elsewhere (despite its shortcomings).

3. Gardasil Is NOT Designed to Protect Against Only Two Strains

Here Dr. Mercola is flat-out wrong, no sugar-coating. In reality, Gardasil is a “quadrivalent” vaccine, meaning it protectas against 4 strains of HPV. Dr. Mercola is thinking of a different brand of the vaccine, but he should get his facts straight before making extreme claims about the safety and efficacy of a vaccination, as many individuals will take his word rather than conducting research on their own. I would FURTHER add that 70% of cervical carcinomas are caused by HPV-16 and -18, so EVEN if it was JUST those two strains (as is GlaxoSmithKline’s version), this fact would not diminish the relevance of HPV vaccination (http://www.ncbi.nlm.nih.gov/pubmed/21289891). Just for reference and to make sure you understand that I know the distinction, 90% of genital warts cases are caused by HPV-6 and -11 (development of warts and carcinoma is not symmetrical) (http://jid.oxfordjournals.org/content/ 206/6/860.abstract). Keep in mind also that there is also a degree of cross-protection in the vaccine for other strains as well.

4. The Waning of Gardasil-Induced Immunity

One point of Dr. Mercola’s that I will grant is that the efficacy of the vaccine in preventing cervical cancer that may develop 20-40 years post-vaccination has not been established. That said, I would like to point out that young women are at the highest risk for HPV infection, and Gardasil protects them during this vulnerable stage of their lives. In fact, prevalence of HPV infection ishighest among females age 20 to 24 years (44.8 percent) (http://www.medical newstoday.com/releases/64119.php).

5. Education

No one disagrees that in many circles the vaccine is mis-represented. Yes, education is important, and people need to understand what HPV is and how it relates to cervical cancer. This point is rather tangential to whether or not women/men should be vaccinated. I could have an entire post on the public information regarding the vaccine.

6. Efficacy Based on Age

The HPV vaccination is indeed more effective in younger individuals, who are less likely to have had sexual partners and been exposed to any strain of the virus. While not worthless among adults with more sexual partners, these individuals will be less protected — that’s all. No one disagrees here. (http://www.ncbi.nlm.nih.gov/pubmed/ 23199956). Again, none of this means that we shouldn’t vaccinate.

Moving on…

Intermediate outcomes are a necessary measure in science. Once a vaccine or treatment is available, it is rarely put “on hold” because follow-up was limited to 5 years rather than 20, especially when alternatives are not available. In the case of HPV, “high-grade cervical lesions” are considered a reliable predictor of increased probability for the development of invasive cancer, which can take years after infection to become clinically detectable. Would we never have started using penicillin if we had to wait 20-40 years before seeing whether or not it had any adverse effects?  Sometimes scientifically plausible links need to be established, at least in the interim and when justifiable according to the evidence.

Some strong supporting evidence:

Australia was the first country to implement a universal government-funded HPV vaccination program. When Australia provided free quadrivalent HPV vaccination to girls aged 12-18 between mid-2007 and the the end of 2009, diagnosis of genital warts in new patients to the Melbourne Sexual Health Centre declined in women under age 21 from 18.6% to 1.9%. In woman over 30 (who did not receive free vaccination), there was no change (not exactly a “control” but as close as ethically possible). Analysis was adjusted for the number of sexual partners, which might otherwise have been a confounding factor. Furthermore, prevalence of other STIs in the clinic continued to increase, coinciding with the “expected” trend, which would seem to indicate that the decreased prevalence of genital warts was not coincidental (http://sti.bmj.com/content/87/7/544.long). The same trend was observed in a Swedish study, among others (http://jid.oxfordjournals.org/content/206/6/860.abstract).

In New Zealand, a similar program was initiated in 2008. Between 2007 and 2010, the rates of genital warts in women under 20 years who visited the Auckland Sexual Health Service decreased from 13.7% to 5.1%. In women over 20 the decrease was 7.6% to 5.9%. (http://www.ncbi.nlm.nih.gov/pubmed/21952330)

Anyway, I could go on and on. The HPV vaccine pushed us forward leaps and bounds, and made an immense difference in the prevalence of HPV in many parts of the world. Only time will tell whether cervical cancer diagnoses diminish, but all scientific evidence points toward the expectation that it will. Please do not let your fear of the unknown lead you to accept vaccination paranoia. In one social psychology experiment, researchers went around telling people that “dihydrogen monoxide” was slowly poisoning everyone, and asked individuals to sign a petition for its ban. Not knowing that H2O is water, nearly everyone signed. Don’t make the same mistake when thinking about the science behind vaccinations like Gardasil.

Advertisements

Metabolism of Fructose Versus Glucose

Posted on

Image not available.

Fructose and glucose are metabolized differently by the body, with some individuals including Dr. Robert Lustig hypothesizing that fructose may be the cause of the rising obesity epidemic in America. There are many differences between the two monosaccharides (another word for single-ringed sugars, as opposed to disaccharides like sucrose — see image below), but they have the same molecular formula (i.e. the same number of carbon, hydrogen, and oxygen atoms). However, glucose has a six-member ring, and fructose a five-member one. Keep in mind that fructose is an intermediate in glucose metabolism (i.e. glucose is converted into fructose at one stage in glycolysis), but that does not mean they have identical effects on the body. For instance, fructose stimulates the secretion of insulin more weakly than does glucose, as well as other peptides involved in appetite regulation.

sugar

The hypothalamus is the region of the brain generally considered to control feeding behavior. The thalamus is considered the sensory “relay center” of the brain, filtering all stimuli, and the hypothalamus sits just beneath it (it’s about the size of an almond). It has projections to the pituitary gland, so it controls the fight or flight instinct. For instance, its cells produce many hormones, including thyrotropin-releasing hormone, growth-hormone releasing hormone  (sounds repetitive, right?! It’s just another complex and highly regulated function of our endocrine system!), and vasopressin and oxytocin (the “bonding” hormones, among other things).

Regional cerebral blood flow (CBF) is considered a valid but imperfect marker of neural activation. Think of the occipital lobe of the brain (which sits in the back, above the cerebellum) lighting up when a subject sits in an MRI machine while engaging vision-based tasks. Interestingly in one study, glucose administration reduced hypothalamic CBF within 15 minutes, while fructose did not. (http://jama.jamanetwork.com/article.aspx?articleid=1555133). As the picture above shows, blue regions indicate areas with decreased CBF after fructose or glucose ingestion. You can see that the hypothalamus lit up in the glucose condition (indicating decreased flow); this is a rough approximation, and it’s interesting that fructose led to decreased activation of the hippocampus, a region of the brain involved in memory. I will not speculate on why this result might have occurred, because there is simply too little evidence to draw a conclusion.

Other evidence to support the differential processing of glucose and fructose is a study in 2009 that showed fructose-sweetened, but not glucose-sweetened, beverages increased visceral adiposity (fat) in overweight/obese humans. (http://www.ncbi.nlm.nih.gov/pubmed/19381015) Also in this study, fasting small dense LDL (the bad kind of cholesterol) decreased at 2 weeks in subjects consuming glucose, but increased in subjects consuming fructose.

So here’s a big piece of the equation: fructose metabolism occurs independently of phosphofructokinase (http://ajcn.nutrition.org/content/58/5/754S.long), so that there is no negative feedback loop limiting its metabolism by the liver (as occurs with glucose consumption).  When glucose is absorbed by liver cells, it goes through an extensive process involving, at one point, a phosphorylation step. Phosphorylation is a key regulatory process in the cell, whereby a phosphate group (the same kind in the backbone of our DNA) is attached to a molecule, usually for the purpose of “signaling” another protein/molecule. “Kinases” are enzymes (a type of protein) that typically attach phosphate groups to other molecules.

The liver initially takes up about 50% of the fructose we ingest (considered a high rate of extraction). This fructose is phosphorylated in the liver by fructokinase, and is then split into two smaller molecules (glyceraldehyde and dihydroxyacetone phosphate). After glyceraldehyde is phosphorylated, the glucose and fructose pathways “coverge” (i.e. have same end-products, and by end-products I mean intermediate molecules).

However, the rate-controlling step of glycolysis is catalyzed by phosphofructokinase. Notably, phosphofructokinase is inhibited by ATP and citrate, which are end-products of glycolysis (this is one way in which glucose metabolism is regulated). As a result, fructose is rapidly phosphorylated when it is presented to the liver. Basically there is increased “traffic,” so to speak, through glycolysis. Usually, a negative feedback loop regulates this system, and the accumulation of fructose-1,6-biphosphate inhibits glycolysis. However, fructose ingestion does not lead to fructose-1,6-biphosphate accumulation (I know it’s counter-intuitive given that there is a “fructose” in the name, but it just happens to be a product in glucose metabolism).  Remember that glucose is first converted to fructose when it enters the cell.

Now, consumption of fructose has spiked over the last 4 decades. I won’t bother you with the number of grams per person, but here’s a graph just to give you an idea: (http://physrev.physiology.org/content/90/1/23.long)

F1.large
This post has quickly become much longer than I intended it to be, but it turns out this is a complicated subject (who knew! Not like the thousands of research papers on obesity should be a hint…literally 171645 papers in Pubmed come up if you search the word!). Anyway — I won’t pretend to have covered the entirety of existing literature on fructose and glucose, but this tidbit should give you an idea of some of the key differences, and why fructose is such a topic of interest lately. For a fascinating talk by Robert Lustig, watch this video. In the interest of not boring you to tears right now, I’ll discuss how this metabolic pathway leads to fat storage in a later post!

Salt is Not the Enemy

Posted on

Apparently, salt is not the enemy.  There is a fascinating article in the New York Times, by Gary Taubes, on how little evidence supports the “anti-salt” mission of certain groups. 

http://www.nytimes.com/2012/06/03/opinion/sunday/we-only-think-we-know-the-truth-about-salt.html?pagewanted=1&_r=0&smid=tw-share

 

Chris Kresser also discusses the issue in a series of posts. They are worth reading, especially if you know people who subscribe to the “low sodium” ideology!

http://chriskresser.com/salt

Why I Started This Blog

Posted on

I’ve been eating a mostly paleo/primal diet for several years now, and I used to accept the generic justifications.  Several months ago I decided that these “paleoisms” weren’t good enough for me, and I went on a quest to find some science to back up the blogosphere’s claims.  I am somewhat sad to say that the science was largely lacking from many sites, with some notable exceptions.  There isn’t much out there that falls somewhere in between an overly in-depth analysis of biochemical pathways and inaccurate references to those things called “lectins” and “phytates” (more on these later).  I recently discovered some amazing individuals in the paleo/primal community who truly know what they’re talking about, but some of the information out there still needs to be digested.  My hope is that in some small way I can fill in the holes (heheh leaky gut anyone?) in your knowledge.

I feel fairly confident in assuming that for those of you who stick to the paleo principles, you’ve been asked at some point “why” you eat this crazy “diet.”  I mean COME ON, what the hell?  Someone made a delicious cake for a friend’s birthday and you won’t eat it?  You don’t dive into that homemade baklava your aunt made especially because you were coming?  Ok, maybe that one’s just me.  Food is central to our social culture, and many people find it distressing to meet someone whom they can’t feed.  CRAZY, right?  Well, I guess it doesn’t really matter, because that’s how it is.

SO, next time you’re confronted with WHY you eat paleo/primal, wouldn’t you love love LOVE to have a solid reason, other than “because our ancestors ate a diet high in animal protein and vegetables, and the diseases of modern civilization only emerged with the advent of agriculture.”  Few people find this reason acceptable, and I hope I can help show you that you don’t need to fall back on such a weak explanation.

I am not one of those individuals who were cured of an autoimmune disease by a paleo diet.  I’m a “normal” 20-something female who just likes eating this way, but recognizes that this justification won’t fly in most audiences.  I have a Bachelor’s degree in Neurobiology from Harvard, so I know a little something about science.  There’s always more to learn though.  Hopefully we can learn together.