Hi, fellow PaleoHackers,
After being on the receiving end of multiple emails from extended family members who are MDs which at times implied and other times outright asserted that we were irresponsible parents for feeding our kids paleo-style and ill-equipped (since we aren't MDs) to make our own judgments on what constitutes good nutrition, I finally sent an email in defense of our choices (to that point we had been trying to keep the peace). My email included the below citations. The MD relative replied that it was plain from reading my citations/commentary that such things were, "said by someone who has very little if no medical knowledge."
OK, so I am most definitely NOT an MD. I had one year of premed in college, and after that ended up getting two undergrad degrees and a grad degree in another field.
BUT, I want to improve my layman rough interpretations of these studies - not necessarily for this relative's sake, because I think that she and her MD husband will remain perpetually unconvinced - but for my own understanding and in case I decide to use some or all of the same citations again. Frequent citation of peer reviewed studies is one of the things I cherish about the paleo community, so it's a skill I'd like to hone a bit more.
Help me out, where is my "non-MD" fly hanging open? How can I do better?
From the Journal of the American Heart Association, published in 2003. "Efficacy and Safety of Low-Carbohydrate Diets" http://jama.ama-assn.org/content/289/14/1837
High fat high protein low carb diets do not negatively affect bloodwork or blood pressure, as said in the abstract:
"Low-carbohydrate diets had no significant adverse effect on serum lipid, fasting serum glucose, and fasting serum insulin levels, or blood pressure."
In Cancer, Epidemiology, Biomarkers and Prevention, published in 2004 http://cebp.aacrjournals.org/content/13/8/1283.abstract
It is sugar intake, not fat intake, that was associated with an increased risk of developing breast cancer.
"Among carbohydrate components, the strongest associations [with breast cancer] were observed for sucrose and fructose. No association was observed with total fat intake. Discussion: In this population, a high percentage of calories from carbohydrate, but not from fat, was associated with increased breast cancer risk. This relation deserves to be investigated further, particularly in populations highly susceptible to insulin resistance."
Via National Institutes of Health, originally published in 2004 in the American Journal of Clinical Nutrition "Dietary fats, carbohydrate, and progression of coronary atherosclerosis in postmenopausal women." http://www.ncbi.nlm.nih.gov/pubmed/15531663?ordinalpos=76&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum
A study showing that increased saturated fat intake had less progression of coronary atherosclerosis, whereas increased carbohydrate intake showed increased progression of coronary atherosclerosis.
"CONCLUSIONS: In postmenopausal women with relatively low total fat intake, a greater saturated fat intake is associated with less progression of coronary atherosclerosis, whereas carbohydrate intake is associated with a greater progression."
This one comes from the American Journal of Clinical Nutrition, published in 2009. http://www.ajcn.org/content/early/2010/01/13/ajcn.2009.27725.abstract
Simply said, it says there is no compelling evidence to conclude that saturated fat intake is linked with an increased risk of coronary heart disease or cardiovascular disease.
"Conclusions: A meta-analysis of prospective epidemiologic studies showed that there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD [coronary heart disease] or CVD [cardiovascular disease]. More data are needed to elucidate whether CVD risks are likely to be influenced by the specific nutrients used to replace saturated fat."
Again, via National Institutes of Health, originally published in 2009 in Cardiovascular Diebetology, a study titled "Beneficial effects of a Paleolithic diet on cardiovascular risk factors in type 2 diabetes: a randomized cross-over pilot study." http://www.ncbi.nlm.nih.gov/pubmed/19604407
A paleolithic diet did a better job than a standard "diabetes diet" at improving glycemic control and several cardiovascular risk factors.
"CONCLUSION: Over a 3-month study period, a Paleolithic diet improved glycemic control and several cardiovascular risk factors compared to a Diabetes diet in patients with type 2 diabetes."
NIH, again, originally published in the American Journal of Clinical Nutrition in 2010. "Saturated fat, carbohydrate, and cardiovascular disease." http://www.ncbi.nlm.nih.gov/pubmed/20089734
There is no compelling evidence that eating more carbohydrates instead of saturated fat is a beneficial choice.
"...there are few epidemiologic or clinical trial data to support a 'benefit of replacing saturated fat with carbohydrate."
Via NIH, published in 2009 in the European Journal of Clinical Nutrition: "Metabolic and physiologic improvements from consuming a paleolithic, hunter-gatherer type diet." http://www.ncbi.nlm.nih.gov/pubmed/19209185
Even in a case where weight loss isn't the goal, a paleolithic type diet improves blood pressure, glucose tolerance, insulin sensitivity, and lipid profiles - and also decreases insulin secretion.
"CONCLUSIONS: Short-term consumption of a paleolithic type diet improves BP and glucose tolerance, decreases insulin secretion, increases insulin sensitivity and improves lipid profiles without weight loss in healthy sedentary humans."
The European Journal of Clinical Nutrition, published in 2010. "Dairy consumption and patterns of mortality of Australian adults" http://www.nature.com/ejcn/journal/v64/n6/abs/ejcn201045a.html
Full fat dairy consumption is not found to be a cause of death, but in fact is seen to be possibly beneficial in the protection of death from heart disease.
"Overall intake of dairy products was not associated with mortality. A possible beneficial association between intake of full-fat dairy and cardiovascular mortality needs further assessment and confirmation."
In The Lancet, 2003. "Coeliac disease." http://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2803%2914027-5/abstract
The full text notes that up to 30 percent of people of European descent carry the genes responsible for celiac disease, which is also mentioned (with figures at 35-40%) here by Dr. Sheila Crowe, MD.
From the American Journal of Gastroenterology, in 2011, via the National Institutes of Health. "Gluten causes gastrointestinal symptoms in subjects without celiac disease: a double-blind randomized placebo-controlled trial." http://www.ncbi.nlm.nih.gov/pubmed/21224837
Patients without celiac disease still decline measurably and signficantly in symptoms of pain, bloating, stool consistency, and tiredness when consuming gluten for 1 week.
"On a visual analog scale, patients were significantly worse with gluten within 1 week for overall symptoms (P=0.047), pain (P=0.016), bloating (P=0.031), satisfaction with stool consistency (P=0.024), and tiredness (P=0.001)."
"CONCLUSIONS: "Non-celiac gluten intolerance may exist..."
From the journal Gastroengerology, 2009. "Increased prevalence and mortality in undiagnosed celiac disease." http://preview.ncbi.nlm.nih.gov/pubmed/19362553?itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum&ordinalpos=2
American wheat strains have been bred specifically over the last century to boost cultivated wheat's gluten content to unprecedented levels, which could explain in part the reason why celiac disease is on the rise. In the last 50 years alone incidences of full-blown celiac disease have gone up 400 percent.
"CONCLUSIONS: During 45 years of follow-up, undiagnosed [celiac disease] was associated with a nearly 4-fold increased risk of death. The prevalence of undiagnosed [celiac disease] seems to have increased dramatically in the United States during the past 50 years."
From the Annals of Medicine, 2010. "Natural history of celiac disease autoimmunity in a USA cohort followed since 1974" http://informahealthcare.com/doi/abs/10.3109/07853890.2010.514285
Note: Wheat has been increasingly bred - particularly over the last 100 years - to have maximal gluten content in order to make breads lighter and fluffier, potentially underlying the boom in celiac cases (and not just in diagnosed cases; the proporition itself has truly increased).
"Conclusions. During a 15-year period CD prevalence increased 2-fold in the CLUE cohort and 5-fold overall in the US since 1974. The CLUE study demonstrated that this increase was due to an increasing number of subjects that lost the immunological tolerance to gluten in their adulthood."
From the journal Neurology, published in September 2010, via National Institutes of Health: "Sensory ganglionopathy due to gluten sensitivity." http://www.ncbi.nlm.nih.gov/pubmed/20837968
Those sensitive to gluten can experience tingling or numb extremities when exposed to gluten.
"Gluten sensitivity can engender neurologic dysfunction, one of the two commonest presentations being peripheral neuropathy. The commonest type of neuropathy seen in the context of gluten sensitivity is sensorimotor axonal."
"CONCLUSIONS: Sensory ganglionopathy can be a manifestation of gluten sensitivity and may respond to a strict gluten-free diet."
From the journal Lancet Neurology, published in 2010. http://www.ncbi.nlm.nih.gov/pubmed/20170845 "Gluten sensitivity: from gut to brain"
This says that you do not have to be a diagnosed celiac to suffer brain fog from having gluten in your system, if your system is sensitive to gluten.
"Although neurological manifestations in patients with established coeliac disease have been reported since 1966, it was not until 30 years later that, in some individuals, gluten sensitivity was shown to manifest solely with neurological dysfunction."
From Medical Hypotheses, 2010. "The gluten syndrome: a neurological disease." http://www.ncbi.nlm.nih.gov/pubmed/19406584
Even those with no clinical evidence of mucosal gut damage (diagnosis of celiac disease) can still exhibit gluten sensitivity, including nerological symptoms.
"The crucial point, however, is that gluten-sensitivity can also be associated with neurological symptoms in patients who do not have any mucosal gut damage (that is, without celiac disease). Gluten can cause neurological harm through a combination of cross reacting antibodies, immune complex disease and direct toxicity."
From Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association, 2009. "Gluten sensitivity in patients with IgA nephropathy." http://www.ncbi.nlm.nih.gov/pubmed/19332868
Conclusions note that study subjects did not necessarily need to be celiac diagnosed to suffer digestive disorder/inflammation from consuming gluten.
"CONCLUSION: It is concluded that approximately one-third of our IgAN patients have a rectal mucosal sensitivity to gluten, but without signs of coeliac disease, and we hypothesize that such sub-clinical inflammation to gluten might be involved in the pathogenesis of IgAN in a subgroup of patients."
From the Journal of Neurology, Neurosurgery, and Psychiatry, in 2009 "Hippocampal sclerosis in refractory temporal lobe epilepsy is associated with gluten sensitivity." http://www.ncbi.nlm.nih.gov/pubmed/19244266
In this analysis, epilepsy is connected with gluten sensitivity (and not just celiac disease).
"CONCLUSIONS: The present study demonstrates a previously unrecognised link between gluten sensitivity and [temporal lobe epilepsy] with [Hippocampal sclerosis]. This association was very robust in this well-characterised group of patients; thus gluten sensitivity should be added to the list of potential mechanisms leading to intractable epilepsy and HS."
From the Spanish Society of Digestive Pathologies, 2008 "[Relapsing acute pancreatitis associated with gluten enteropathy. Clinical, laboratory, and evolutive characteristics in thirty-four patients]" http://www.ncbi.nlm.nih.gov/pubmed/19222332
Concludes that the current only effective therapy for acute pancreatitis is a gluten-free diet.
"CONCLUSIONS: Relapsing AP with GE represents a relatively common association that is indistinguishable from other APs from a clinical-evolutive standpoint, except for a lower presence of cholelithiasis (p < 0.05). A specific diagnostic protocol is much needed in the identification of these patients since GFD is the only effective therapy to prevent new AP events from developing."
In Nature Neuroscience, published in 2004. "High cholesterol level is essential for myelin membrane growth" http://www.ncbi.nlm.nih.gov/pubmed/15793579
Cholesterol plays an essential role in myelin growth. Myelin degeneration is a key aspect of multiple sclerosis; indeed, I have a friend whose MS symptoms (she couldn't even button her shirt) completely abated when she went from a conventional low fat high grain diet to a high fat, gluten free paleo diet.
The study notes: " This shows that cholesterol is an indispensable component of myelin membranes and that cholesterol availability in oligodendrocytes is a rate-limiting factor for brain maturation."
The Tokelau Island Migrant Study http://wholehealthsource.blogspot.com/2009/01/tokelau-island-migrant-study-final-word.html
You can find the entire Tokelau study (originally published in 1992) in the American Journal of Epidemiology: http://aje.oxfordjournals.org/content/139/8/844.extract
"One of the most interesting things about Tokelauans is their extreme saturated fat intake, 40- 50% of calories. That's more than any other population I'm aware of. Yet Tokelauans appear to have a low incidence of heart attacks, lower than their New Zealand- dwelling relatives who eat half as much saturated fat. This should not be buried in the scientific literature; it should be common knowledge."
"What we can say is that an increase in the consumption of modern foods on Tokelau, chiefly white wheat flour and refined sugar, correlated with an increase in several non-communicable disorders, including overweight, diabetes and severe tooth decay. Further modernization as Tokelauans migrated to New Zealand corresponded with an increase in nearly every disorder measured, including heart disease, weight gain, diabetes, asthma and gout. These are all 'diseases of civilization', which are not observed in hunter-gatherers and certain non-industrial populations throughout the world."