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Teaser Excerpt from The Paleo Approach: Probiotic Supplements

February 18, 2013 in Gut Health, Supplements, The Paleo Approach Excerpts

The Paleo Approach by Sarah BallantyneLast week I posted a teaser excerpt from The Paleo Approach about the importance of including probiotics (while the book is written from the perspective of autoimmune disease, the benefits of probiotics extend to all health conditions and human health in general).  However, there are many people who don’t do well with fermented foods (reasons might include a yeast sensitivity, which is common in people with gluten intolerance, or a histamine sensitivity) or who just plain old don’t like them.  So, it’s no surprise that that post prompted a series of questions about probiotic supplements.  I have decided to share another excerpt from the book with you to help answer the question of probiotic supplements.

I should probably mention that both of the specific brands of probiotics mentioned in this section are ones that I take myself (and chose after a great deal of research).  I’ve been taking these for 4 or 5 months and really like both of them.  I also heard Chris Kresser rave about Prescript-Assist in his most recent podcast (just in case you were looking for a second opinion!).

This excerpt is from Chapter 8 (the supplements chapter).

As mentioned in Chapter 6,different strains of probiotics confer different effects on your body.  However, from the vast array of different probiotic bacteria (approximately 35,000 species), only a handful have been characterized.

As previously mentioned, probiotic supplementation was shown to be beneficial for the management of every autoimmune disease in which it has been tested, including: inflammatory bowel disease, autoimmune myasthenia gravis, celiac disease, rheumatoid arthritis, multiple sclerosis, and autoimmune thyroid disease.  However, it is important to note that there is also some conflicting information.  In fact, there is convincing evidence that both bifidobacterium and lactobacillus probiotic bacteria (the two most common bacterial genera in probiotic supplements) are a source of autoantibody formation through molecular mimicry in autoimmune thyroid disease (discussed in Chapter 2).  Furthermore, there have been reports of severe eosinophilic syndrome—a condition characterized by elevated eosinophils (a type of white blood cell important for the innate immune system) in the blood with damage to cardiovascular system, nervous system, and/or bone marrow—directly attributable to the use of probiotics (both in people with a history of autoimmune disease but also in completely healthy individuals).

What does this mean?  If you do not tolerate fermented foods, probiotics are definitely worth trying.  The majority of the evidence in the scientific literature supports their potential benefits; however, some caution is advisable.  Just as in the case of fermented foods, probiotic supplements can be added after following The Paleo Approach for several weeks (at least 3) in the case of people with severe gastrointestinal symptoms or known bacterial overgrowth.

Which probiotics should you take? Probiotic supplements fall into two categories:

kirkman bio goldLactobacillus/Bifidus:  Lactobacillus and bifidobacterium are the two most heavily studied genera of probiotic bacteria.  They are also the most commonly found in supplement form.  It is important to note that even though the majority of scientific studies show health benefits of these strains, these are also the strains that may contribute to autoantibody formation and to severe eosinophilic syndrome in some people.

If you choose to take a lactobacillus and bifidobacterium supplement, look for a brand with as many different strains as possible (for greater probiotic diversity).  However, be cautious:  dairy ingredients are common in these types of supplements.  Look for a bottle that specifically brands itself as dairy-free, gluten-free, soy-free, corn-free, wheat-free, egg-free, peanut-free, and tree nut-free.  Also look for one that is yeast-free if the reason you are taking a probiotic supplement instead of eating fermented foods is yeast sensitivity concerns.  One high-quality brand to look for is Kirkman.

Start with a low dose, even breaking open a capsule and sprinkling a small amount in your food or in a small cup of water.  Alternatively, you can take your probiotic supplement every 2 or 3 days.  Over the course of several weeks, work your way up to the suggested dose on the bottle, taken daily.  Some probiotic supplements recommend taking with food while other recommend taking them on an empty stomach.  It is typically best to follow the specific recommendation of the brand you are using.  If your probiotic supplement does not have directions regarding whether or not to take it with food, first try taking it on an empty stomach.  After several weeks, switch to taking with food and see if you notice any improvement.

prescript-assist-probiotic-largeSoil-Based Organisms:  While not as extensively studied as probiotics from the lactobacillus and bifidobacterium genera, soil-based organisms hold extreme promise for modulating the immune system and correcting gut dysbiosis.  They have been shown to have extreme therapeutic potential in Irritable Bowel Syndrome and provide probiotic organisms that are routinely missing from our modern, over-hygienic lifestyles yet are normal residents of a healthy gut.

One brand to look for is Prescript-Assist which contains 29 different strains of soil-based organisms and is also dairy-free, gluten-free, soy-free, corn-free, wheat-free, egg-free, peanut-free, tree nut-free and yeast-free (also none of the strains included in Prescript-Assist come from the lactobacillus or bifidobacterium genera, or indeed any of the strains typically found in fermented foods).  Prescript-Assist has one of the best diversity of any probiotic supplements available.  Soil-based organisms seem to be better tolerated than lactobacillus and bifidobacterium, although extensive comparisons have not been made.

It is typically recommended to take two capsules daily (divided into two doses) for thirty days, followed by one capsule once or twice per week as a maintenance dose.  Because the strains in soil-based organism probiotics are different from the probiotic strains typically found in fermented foods, it is worth strongly considering taking a soil-based probiotic even if you are eating fermented food or taking a lactobacillus and bifidobacterium-based probiotic supplement.

Bittner AC, Croffut RM & Stranahan MC, Prescript-Assist probiotic-prebiotic treatment for irritable bowel syndrome: a methodologically oriented, 2-week, randomized, placebo-controlled, double-blind clinical study, Clin Ther. 2005 Jun;27(6):755-61.

Bittner AC, et al., Prescript-assist probiotic-prebiotic treatment for irritable bowel syndrome: an open-label, partially controlled, 1-year extension of a previously published controlled clinical trial, Clin Ther. 2007 Jun;29(6):1153-60

Jirillo E, Jirillo F & Magrone T, Healthy effects exerted by prebiotics, probiotics, and symbiotics with special reference to their impact on the immune system, Int J Vitam Nutr Res. 2012 Jun;82(3):200-8

Kiseleva EP, et al., The role of components of Bifidobacterium and Lactobacillus in pathogenesis and serologic diagnosis of autoimmune thyroid diseases, Benef Microbes. 2011 Jun;2(2):139-54.

Klaenhammer TR, et al., The impact of probiotics and prebiotics on the immune system, Nat Rev Immunol. 2012 Oct;12(10):728-34

Kverka M & Tlaskalova-Hogenova H, Two faces of microbiota in inflammatory and autoimmune diseases: triggers and drugs, APMIS. 2012 Oct 24.

Mendoza FA, et al., Severe eosinophilic syndrome associated with the use of probiotic supplements: a new entity?, Case Report Rheumatol. 2012;2012:934324

Veerappan GR, Betteridge J &Young PE., Probiotics for the treatment of inflammatory bowel disease, Curr Gastroenterol Rep. 2012 Aug;14(4):324-33.

Vyas U & Ranganathan N., Probiotics, prebiotics, and synbiotics: gut and beyond, Gastroenterol Res Pract. 2012;2012:872716.

 

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The Benefits of Probiotics –Teaser Excerpt from The Paleo Approach

February 12, 2013 in Gut Health, Supplements, The Paleo Approach Excerpts

The Paleo Approach by Sarah BallantyneThere are many topics that I am researching and writing about for the book that I’ve been meaning to write about for the blog for ages (the book just gives me a firm deadline).  I have decided take some of these topics (especially the more blog-sized ones) and publish them as teaser excerpts for the book (also because I think this information should be here too).

The book also contains a detailed (yet easy-to-follow) description of the components of the immune system, so when you read the book, you’ll already know why modulating Th1 versus Th2 versus regulatory T-cells is important and you’ll know what dendritic cells, antigen presentation and cytokines are. For a quick primer: Th1 and Th2 cells are over-activated in autoimmunity and cause damage (typically one or the other is over-activated).  Regulatory T-cells are supposed to keep all the other immune cells in check and suppress both over-activation of the immune system and autoimmunity (they tend to be deficient in autoimmune disease).  Cytokines are chemical messengers of inflammation.  Dendritic cells are a type of sentinel cell that detects foreign invaders.  Antigens are small sequences of amino acids on foreign invaders that are recognized by the immune system.   When a dendritic cell detects foreign invaders, they “show” the antigens to B-cells and T-cells (cells of the adaptive immune system).  Gut-Associated Lymphoid Tissue is the collection of immune cells and other tissues just inside the intestinal barrier in the gut.  Enterocytes are the cells that line the small intestine and form the barrier between inside the gut and outside the gut.

So, forgive the references to Chapters 2, 3, 8 and 12.  While you’ll have to wait until the book is out in September to read those sections, in the meantime, please enjoy this part of my section of probiotics (actually, probiotics are talked about in 4 separate sections-this section is from the chapter on healing foods).

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Consumption of probiotics, either as a supplement or in the form of unpasteurized fermented foods, can dramatically help modulate the immune system.  A vast number of scientific and clinical studies have evaluated the various effects of the commensal bacteria in the gut (those healthy gut bacteria) and/or probiotic supplement of specific bacterial strains on various aspects of the immune system.  The cliff notes?  It’s all good.

The exact mechanisms behind the many observed benefits of probiotics remain largely unknown.  This may be because different bacterial strains have different effects on the body and interact differently with the immune system.  For example, some probiotic strains stimulate production of cytokines (those chemical messengers of inflammation) that promote Th1 cell development (which may augment the immune system to help fight infection and prevent cancer).  Other probiotic strains stimulate production of cytokines that promote regulatory T-cell development, thereby providing that all important immune system modulation needed in autoimmune disease (see Chapter 2).  Yet other probiotic strains, including several lactobacillus strains, are beneficial both in diseases of compromised immune systems and diseases of excessively activated immune systems.

It has been shown that probiotics interact with dendritic cells during antigen presentation during the initiation of adaptive immune responses, meaning that probiotics are useful in preventing immune-related diseases (see Chapter 2).  However, they also affect the effector phase of adaptive immunity, so they can be used as a treatment for established immune-related diseases (this applies to both immune-related diseases like asthma and allergies but also autoimmune diseases).  In fact, probiotic supplementation has been shown to be beneficial in a variety of autoimmune conditions, including:  autoimmune myasthenia gravis, inflammatory bowel diseases, rheumatoid arthritis, multiple sclerosis, and autoimmune thyroid disease.

It used to be believed that probiotic supplementation and the consumption of unpasteurized fermented foods provided health benefits by re-inoculating the gut with beneficial strains of bacteria and yeast.  Having a healthier variety and types of gut microorganisms would then be responsible for the positive benefits of probiotic supplementation.  However, recent scientific research puts this explanation into doubt—at least in some cases.  A recent study of diarrhea-predominant Irritable Bowel Syndrome demonstrated that the administration of probiotic supplements did not to alter the composition of the gut microflora.  It’s important to emphasize that probiotic supplementation was still beneficial.  This implies that the benefits of probiotic consumption might be directly due to the interaction of those probiotic bacteria (and yeast) with the gut-associated lymphoid tissue (see Chapter 2) as it passes through the body, at least in some cases.

There are clearly still some situations where probiotic supplements do have profound effects on the gut microflora.  For example, studies have shown differences in the composition of the gut microflora after taking antibiotics in people who supplemented with probiotics compared to those who didn’t.  There may also be more impactful effects on those with bacterial overgrowths.  Probiotic microorganisms have the capability to affect the gut microflora through a variety of mechanisms, including: reducing the acidity in the intestinal lumen (the area in the middle of the “tube” that forms the gut), competition for nutrients, secretion of antimicrobial compounds by the probiotics themselves, stimulating the production of antimicrobial compounds by your cells, and preventing adhesion and interaction of other bacteria with gut epithelial cells.  In these ways, probiotics may help to “correct” gut dysbiosis.

Beyond restoring balance to the gut microflora and modulating the immune system, research has shown that administration of probiotics can have a direct effect on the tight junctions between enterocytes in the gut—resulting in decreased intestinal permeability.  So, taking a probiotic or eating food naturally rich in probiotic organisms can directly help heal a leaky gut.

As already mentioned in Chapter 3, what you eat has a profound effect on the types, relative quantities and location of different bacteria growing in your gut—this effect is largely independent of the benefits of consuming fermented foods or taking probiotic supplements.  However, consuming probiotics has the great potential to speed healing and modulate the immune system and should not be underrated in importance when dealing with autoimmune disease.

Some researchers are taking on the task of characterizing the precise effects of each probiotic strain on the human body (recall that there are approximately 35,000 of them among all humans).  Certainly some strains have already been isolated for their anti-inflammatory and immune modulatory properties, yet others for their abilities to improve the barrier function of the gut or the ability to reduce visceral hypersensitivity.  It is completely possible that in the future, probiotic supplements will be tailored to address specific health problems by providing specific strains known to counteract those issues.  However, until then, the best focus is on variety.

Because different probiotic strains have slightly (and sometimes vastly) different effects (which may also depend on your genetics, level of inflammation, and current gut health), the best way to ensure complete modulation/regulation of the immune system is to consume as many different probiotic strains as possible.  So, where do you get variety?  You actually get far more variety from fermented foods and soil than you do from most supplement available (that doesn’t mean that probiotic supplements aren’t useful—see chapter 8 for more information specific to probiotic supplements).  Every time you make a new batch of homemade sauerkraut, the probiotic organisms within it will be slightly different.

So, what are good food sources of probiotics?

  • Raw unpasteurized sauerkraut
  • Raw unpasteurized lactofermented vegetables (kimchee, beets, carrots, pickles)
  • Raw unpasteurized lactofermented fruits (green papaya, chutneys)
  • Raw unpasteurized lactofermented condiments (relishes, salsas)
  • Water kefir
  • Milk kefir grown in coconut milk
  • Kombucha
  • Beet Kvass

Some form of probiotic should be consumed every day.  It is typically understood that a small amount several times per day is more beneficial than a large amount at one sitting.  When you first start consuming probiotic foods, it’s a good idea to keep the amount very small (as little as 1 teaspoon) and see how you feel.  Some people with severe gut dysbiosis can have dramatic gastrointestinal symptoms from probiotics.  If one probiotic food doesn’t work for you, try another.  If none of them work for you, you may have more luck with a supplement or just might need more time to heal your gut before introducing probiotics.  It’s okay if you need to follow The Paleo Approach for a couple of weeks before adding probiotic foods (for more information, see the Troubleshooting section in Chapter 9).  The amount you eat at any given time can then be slowly increased over the course of several weeks.  And of course, you can skip ahead to Chapter 12 to start making probiotic foods in your own home.

An often underrated source of probiotics is soil.  Soil-based organisms (SBOs) have not been as extensively studied as the lactobacillus and bifidus genus of bacteria.  However, they are normal residents of a healthy gut, have been shown to be potent modulators of the immune system, and supplementation with SBOs has been shown to be beneficial in diabetes, chronic fatigue syndrome, insomnia and Irritable Bowel Syndrome.  Soil-based probiotic supplements are available (see Chapter 8 for more information).  You can also get exposure by playing in the dirt (a good excuse to take up gardening as a hobby!) and by growing your own vegetables organically (or buying locally-grown organic vegetables) and eating them without washing them.  Okay, you can rinse the big clumps of dirt off.

 

Barbara, G., et al., Mucosal permeability and immune activation as potential therapeutic targets of probiotics in irritable bowel syndrome, J Clin Gastroenterol. 2012 Oct;46 Suppl:S52-5

Bittner, A.C., et al., Prescript-assist probiotic-prebiotic treatment for irritable bowel syndrome: an open-label, partially controlled, 1-year extension of a previously published controlled clinical trial, Clin Ther. 2007 Jun;29(6):1153-60.

Chae, C.S., et al., Prophylactic effect of probiotics on the development of experimental autoimmune myasthenia gravis, PLoS One. 2012;7(12):e52119.

Corridoni D, et al., Probiotic bacteria regulate intestinal epithelial permeability in experimental ileitis by a TNF-dependent mechanism, PLoS One. 2012;7(7):e42067

Fooks LJ and Gibson GR Probiotics as modulators of the gut flora. Br J Nutr 2002 88(Suppl 1):S39–S49.

Gerritsen, J. et al., Intestinal microbiota in human health and disease: the impact of probiotics, Genes Nutr. 2011 August; 6(3): 209–240.

Kiseleva, E.P., et al., The role of components of Bifidobacterium and Lactobacillus in pathogenesis and serologic diagnosis of autoimmune thyroid disease, Benef Microbes. 2011 Jun;2(2):139-54.

Kobayashi T, et al.,  Probiotic upregulation of peripheral IL-17 responses does not exacerbate neurological symptoms in experimental autoimmune encephalomyelitis mouse models, Immunopharmacol Immunotoxicol. 2012 Jun;34(3):423-33

Le Bert, N., et al., DC priming by M. vaccae inhibits Th2 responses in contrast to specific TLR2 priming and is associated with selective activation of the CREB pathway, PLoS One. 2011 Apr 1;6(4):e18346

Michail, S. & Kenche, H., Gut microbiota is not modified by Randomized, Double-blind, Placebo-controlled Trial of VSL#3 in Diarrhea-predominant Irritable Bowel Syndrome, Probiotics Antimicrob Proteins. 2011 Mar;3(1):1-7

Ng SC, et al., Mechanisms of action of probiotics: recent advances. Inflamm Bowel Dis. 2009;15(2):300–310.

Ruemmele F.M., et al., Clinical evidence for immunomodulatory effects of probiotic bacteria, J Pediatr Gastroenterol Nutr. 2009 Feb;48(2):126-41.

Shida, K. & Nanno, M., Probiotics and immunology: separating the wheat from the chaff, Trends Immunol. 2008 Nov;29(11):565-73.

Shida K, et al., Flexible cytokine production by macrophages and T cells in response to probiotic bacteria: a possible mechanism by which probiotics exert multifunctional immune regulatory activities, Gut Microbes. 2011 Mar-Apr;2(2):109-14

Schiffer, C., et al., A strain of Lactobacillus casei inhibits the effector phase of immune inflammation, J Immunol. 2011 Sep 1;187(5):2646-55

Tlaskalová-Hogenová, H., et al., Commensal bacteria (normal microflora), mucosal immunity and chronic inflammatory and autoimmune diseases, Immunol Lett. 2004 May 15;93(2-3):97-108.

Tsilingiri K & Rescigno M., Postbiotics: what else?, Benef Microbes. 2012 Dec 27:69-75.

Soil-based organisms improve immune function: shift cytokine profile from TH2 to TH1, Posit Health News. 1998 Spring;(No 16):16-8

http://www.old-herborn-university.de/literature/books/OHUni_book_8_article_4.pdf

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The Great Dairy Debate

October 13, 2012 in FAQ, Foods in Moderation, The WHYs of the AIP

The value (or lack thereof) of dairy products is the second most fiercely debated topic within the paleo community (after carbohydrate intake).  Opinions vary dramatically from consumption of no dairy whatsoever, to only consuming dairy fat (such as ghee, butter and heavy cream), to only consuming raw grass-fed dairy, to only consuming fermented dairy or aged cheeses, to including any dairy on a regular basis.

The reason for this diversity of opinions is that the science is not clear cut.  There are strong arguments to be made both for and against.

Let’s start with the arguments against dairy.  Prof. Loren Cordain dedicates an entire well-cited chapter in his most recent book The Paleo Answer (a fantastic book for describing the nitty gritty scientific details behind the paleo diet) to the many reasons why milk should not be consumed in any form.  To summarize, what I view the strongest parts of this argument:

  • Milk is not as nutrient-dense as meat, fruits and vegetables.
  • Milk is highly insulinogenic, meaning it causes a large spike in blood insulin levels, disproportional to the amount of sugar and protein in milk.  This may contribute to the development on insulin resistance, at least in the context of a high carbohydrate diet.  Insulin is also pro-inflammatory.
  • Milk contains active bovine (cow) hormones which have the potential to alter our hormone levels.  The effects of dietary intake of most of these hormones have not been studied.  However, other hormones have been studied.  For example, the milk hormone Insulin-like Growth Factor-1 (IGF-1) has been linked to risk of breast, colorectal and prostate cancer, with the strong indication that consumption of dairy protein is a large contributor to blood IGF-1 levels 1.
  • Milk contains protease inhibitors which may contribute to the development of a leaky gut (see this post for a more in depth explanation as to why)
  • Milk increases mucus production.  This may aggravate conditions such as asthma but also creates excess mucus in the gastrointestinal tract which may irritate the gut lining and inhibit nutrient and mineral absorption.
  • Lactose is poorly tolerated by adults.  Approximately 25% of Caucasians (American and European) are lactose intolerant.  97% of Native Americans are lactose intolerant.  This argument does not apply to drinking raw milk since raw milk contains enzymes to help digest lactose.
  • Dairy is highly allergenic.  This is where I believe the chief argument against dairy lies and I will discuss this further below.

There are also some very compelling arguments for including dairy products in our diets.  Studies have shown that consumption of dairy, especially full-fat dairy products and fermented dairy products, can protect against Metabolic Syndrome (cheese, full-fat dairy, and fermented dairy), Type II Diabetes (fermented dairy only) and Cardiovasular Disease (cheese, full-fat dairy, and fermented dairy) 2-6.

Grass-fed dairy, especially the fat from grass-fed dairy, is an excellent source of fat-soluble vitamins and Conjugated Linoleic Acid, an anti-inflammatory and healing fat.  Fermented dairy is an excellent source of probiotics.  There are also some valuable proteins in dairy, such as glutathione (very important for reducing inflammation and protecting against oxidative stress) and whey (which may help prevent cancer).

There is also evidence that dairy proteins are beneficial for children due to their growth-promoting effects.  Traditionally, children would have received some breast milk until approximately 5 years of age.  In our current society, most children are weaned by age 1.  The current scientific view is that, provided cow’s milk is not introduced too early, it is a good substitute for human milk in terms of its growth promotion 7.

Yes, the science is not clear, although there seems to be a good case for including dairy fat in our diets.  This is why the standard paleo diet allows for ghee and butter, and in many cases heavy cream and full-fat sour cream.  Many people also include fermented dairy in their diets with great success.

However, one thing that is abundantly clear is that milk allergy is common.  Beyond lactose-intolerance, which can be treated with the aid of digestive enzymes or consumption of raw milk, allergy to milk proteins is very common.  Epidemiological reports of cow’s milk allergy (IgE antibody reactions to cow’s milk proteins) range between 1 and 17.5% in preschoolers, 1 and 13.5% in children ages 5 to 16 years, and 1 to 4% in adults 8.  It is not known how prevalent cow’s milk sensitivities are (IgA and IgG antibody reactions to cow’s milk proteins).  It’s important to note that goat’s milk is not as allergenic as cow’s milk.

Cow’s milk proteins are also known gluten cross-reactors, which means that those with gluten intolerance may produce antibodies against gluten that also recognize dairy proteins.  For these people, eating dairy is the same as eating gluten (more information in this post).  Very importantly, for people with allergy, intolerance or gluten cross-reactions to dairy proteins, even the trace dairy proteins in ghee can be a problem.

So, what do I recommend?  Caution.  I believe that dairy is probably okay for many healthy adults, especially full-fat, grass-fed dairy.  In fact, for healthy individuals, the benefits likely outweigh the risks.  However, for those battling autoimmune disease or other conditions where a leaky gut is a potential contributing factor, it makes the most sense to omit dairy from your diet for now.  As is my standard recommendation for all of the gray-area foods, I suggest leaving it out of your diet for at least 1 month, then try reintroducing it and see if you notice any obvious symptoms (this is the best way to determine if you are allergic or sensitive).

I am still trying to gauge my own tolerance for grass-fed butter.  My daughters both seem to do better without cow’s dairy in their diets (except grass-fed butter, which seems okay), but I have reintroduced grass-fed goat mineral whey protein powder into their diets and they seem to do really well with that (especially my oldest).  I also have intentions to try them with some grass-fed goat’s whole milk.  This is another highly individual aspect of a paleo diet and you really don’t know whether or not milk is good for you until you try living without and then try living with.

1. Crowe FL et al “The association between diet and serum concentrations of IGF-I, IGFBP-1, IGFBP-2, and IGFBP-3 in the European Prospective Investigation into Cancer and Nutrition.” Cancer Epidemiol Biomarkers Prev. 2009 May;18(5):1333-40.

2. Louie JC et al “Higher regular fat dairy consumption is associated with lower incidence of metabolic syndrome but not type 2 diabetes.” Nutr Metab Cardiovasc Dis. 2012 Sep 26. pii: S0939-4753(12)00193-7. doi: 10.1016/j.numecd.2012.08.004. [Epub ahead of print]

3. Warensjö E, et al. “Biomarkers of milk fat and the risk of myocardial infarction in men and women: a prospective, matched case-control study.” Am J Clin Nutr. 2010 Jul;92(1):194-202. Epub 2010 May 19.

4. Sonestedt E et al. “Dairy products and its association with incidence of cardiovascular disease: the Malmö diet and cancer cohort.” Eur J Epidemiol. 2011 Aug;26(8):609-18. doi: 10.1007/s10654-011-9589-y. Epub 2011 Jun 10.

5. Sluijs I et al “The amount and type of dairy product intake and incident type 2 diabetes: results from the EPIC-InterAct Study.” Am J Clin Nutr. 2012 Aug;96(2):382-90. Epub 2012 Jul 3.

6. Bonthuis M et al. “Dairy consumption and patterns of mortality of Australian adults” European Journal of Clinical Nutrition (2010) 64, 569–577; doi:10.1038/ejcn.2010.45; published online 7 April 2010

7. Agostoni C and Turck D. “Is cow’s milk harmful to a child’s health?” J Pediatr Gastroenterol Nutr. 2011 Dec;53(6):594-600.

8. http://www.worldallergy.org/publications/WAO_DRACMA_guidelines.pdf

Chris Kresser has a terrific post Dairy: food of the Gods or neolithic agent of disease?

The Paleo Answer by Prof. Loren Cordain is an excellent resource.

 

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Why is Exercise so Important?

September 18, 2012 in Exercise, Hormone Regulation

Let’s get one thing straight:  exercise is not about “burning calories”.  The amount of calories you actually burn exercising compared to sitting and doing nothing is not really that much.  It certainly adds up very slowly when you consider that 3500 calories is equivalent to one pound of stored energy.  If you want to lose weight, focus on your diet (see my post Tips and Tricks For Losing Weight).  But, while diet changes will make the largest contribution to weight loss, it’s important not to ignore exercise!  However, think of exercise as your hormone management, not your calorie burning.

 Hormones are chemical messengers in contact with virtually every cell in your body, sensitive to the demands of your cells, sensing changes in your body’s chemistry, and responding rapidly to ensure that the cells in your body get everything they need to stay healthy.  Exercise has a profound effect on every hormone system in your body.  Whether that exercise is aerobic or anaerobic, cardio intensive or strength training, low-intensity or high-intensity, and short duration or long duration, changes how that exercise affects each hormone system.  It also matters what time of day you exercise, whether or not you exercise in a fasted state, and what other stressors are present (mental stress, lack of sleep, poor quality diet, etc.).  However, what is uniformly true is that exercise is beneficial to hormone regulation. 

 Some of the benefits of exercise are obvious.  Increasing muscle mass causes an increase in metabolism, making it easier to maintain a healthy weight.  Most people like the way they look better when they have bigger and more defined muscles (I do!).   And it’s just plain handy to be stronger, faster, more flexible and more agile.  But there are some additional benefits that you might not immediately think of as you contemplate adding more or different types of activity to your life.  The field of exercise endocrinology (how exercise affects hormones) is enormous and I will be tackling many key areas in upcoming posts.  In particular, I will touch on each of the following benefits to exercise:

 Appetite and Weight Control:  Exercise is known to regulate key hunger hormones such as leptin and ghrelin (I have a whole post on hunger hormones coming soon!) and may even promote healthier digestion through hormone regulation.  It is not necessarily true that exercise makes you hungrier, although it may feel that way.  In fact, for many people (and depending on the type of exercise), exercise makes it easier to naturally consume fewer calories in an entire day (even if you eat a bigger meal right after working out).  Not only does exercise regulate your appetite, but many people find that they naturally crave more nutrient-dense foods.  I myself crave fish and vegetables after an intense workout and while I feel famished, I actually fill up much more quickly than on days that I don’t exercise as much or as intensely.  Exercise is also believed to help lower your bodyweight “set-point” (a controversial idea that basically says that there is a weight which your body “wants” to be, which is determined by your hormones, which are in turn influenced by diet and lifestyle).

 Metabolism and Insulin Sensitivity:  Exercise helps to improve insulin sensitivity through a direct action on the glucose transport molecules in the individual cells of your muscles.  It also affects the full range of hormones related to accessing stored energy and regulating how that energy is used.  This “boost” in metabolism is one reason why exercising can make you feel more energetic throughout the day.

 Body Composition and Bone Health:  When you exercise, your muscles get stronger (and sometimes bigger, depending on the exercise).  This is one contributor to increased metabolism.  And very importantly for long-term health, exercise (especially weight-bearing exercise) stimulates your body to make stronger and denser bones.  Exercise or lack thereof is, in fact, a bigger determinant of osteoporosis risk than diet.

 Stress Management:  Exercise is very effective at modulating cortisol levels.  This is a bit of a double-edged sword because exercising too intensely for your body can increase your cortisol level too high and lead to adrenal fatigue.  However, if you keep exercise to a more appropriate duration and intensity for your fitness level (and appropriate for how well you eat, sleep and manage stress in other areas of your life), exercise becomes very potent at reducing and normalizing cortisol levels (which can also help reduce inflammation and promote healing).  This makes it easier to burn stored energy (especially fat), improves your sleep, and makes you feel more relaxed and able to cope with life’s surprises.

 Sleep Quality:  Beyond its effect on cortisol, exercise regulates several key hormones related to circadian rhythms.  This means that when you exercise during the day, you fall asleep easier, sleep more soundly, and experience more restorative sleep so you wake up feeling more refreshed (providing you allot adequate time for sleeping).  Sleeping better positively affects just about everything in your body, from your cortisol levels to your body’s ability to heal and resolve inflammation.  This is another double-edged sword because exercising too intensely too late in the day can make it more difficult to fall asleep.

 Mood:  Beyond its effect on the stress hormone cortisol, exercise releases endorphins which has a direct reflect on several key neurotransmitters that are related to mood.  This means that making time to exercise can help fight depression and anxiety and improve your general outlook on life.  Exercising also increases blood flow to the brain which can help reduce inflammation in the brain (which also has the net effect of boosting your mood), which is an important strategy for those with gut-brain axis problems.

 What exercise is best?  There are different benefits of exercise, depending on type, duration and intensity, but with the exception of over-training (exercising more too intensely or for too long of a duration for your body and current fitness level), all exercise is extremely beneficial.  What exercise is best for you depends on your goals and your current health status.  As I delve into the specific effects of different types of exercise on different hormone systems in upcoming posts, hopefully you will find enough information to guide your decision making when it comes to prioritizing one activity over another.  But, what matters most is that you do something—even just a gentle stroll.  And even better, do something you enjoy (for me, that’s yoga!).  If you enjoy your activity, you are far more likely to keep doing it.

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