Pardon me,     Server error makes me post here ....
Colon cancer runs in my family & 1st cousin succumbed in his early 40s; USA colon cancer affects +/- 2% of men and +/-1.5% women aged 50 - 70, with higher rates among African-americans. Cancer pathology does not follow lineal constructs, so I will be generalizing (again); colon cancer can be hereditary non-polyposis, familial adenomatous polyposis (polyps), flat adenoma or sporadic colorectal cancer.

Dietary fiber provides the environment for intestinal bacteria to make butyrate for us; and butyrate is beneficial when it produces hydrogen sulfide (H2S). In the large intestine (colon) epithelial cells this butyrate H2S induces a proton "leak" in that cell's mitochondrial electron transfer chain (that cell uses & needs  less oxygen); this uncoupling slows that cell's cycle so that there is less cell division, and simultaneously depresses cytochrome c oxidase 1 & 2 enzymes which prevents that mitochondria from signalling for apoptosis (death). The boost in colonocyte (cellular) H2S also raises that cell's level of the anti-oxidant glutathione; and fosters other beneficial mitochondrial  processes by opening the mitochondrial membrane's K-ATP channel.

Dietary derived H2S comes from sulfurous protein (ie: amino acids methionine, taurine, cysteine & cystine) metabolized by intestinal bacteria;  and more significantly this type of  dietary induced load of H2S depresses the beta-oxidation of butyrate in colonocytes. When it comes to the sexes it is women who more readily produce H2S from sulfurous protein, yet men will produce a higher total amount of H2S; which may indicate why both sexes have similar colon cancer rates.

Sulphur rich cruciferous vegetables (broccoli, cauliflower, brussel sprouts, cabbage & kale) are not high in sulfurous proteins;  metabolism of their sulphur favors a bit more sulphur uptake into local colon tissue than bacterial H2S pathways. Think of the slow steady butyrate H2S output in colonocytes as a pre-treatment; this pre-conditioning is hormetic (hormesis is how a little bit of something potentially dangerous, like H2S, can be good for you that some might phrase as "what doesn't kill you makes you stronger").


Cancer of the colon unfortunately can side-step the preventative action of butyrate H2S when one of the enzymes (cystathine Beta-synthase) butyrate uses to generate H2S gets knocked out. How or why this happens in an individual is not dealt with here; the point is that a certain level of reliable H2S from butyrate will hold down the viabilty of colon cancer cells. Once the colon cancer cell has shifted  it's pheno-type from epithelial pheno-type to mesencymal pheno-type the same cellular protective effects of H2S (see 2nd paragraph above) will then unfortunately help that cancer cell avoid dying (apoptosis).

In a petri dish H2S will kill some colon cancer cell lines; this works because those cancers are not interfacing with the colon's bacterial dynamic. The "nooks and crannys" of the intestinal crypts have 2 distinct mucus (mucin) made up from long chain carbohydrates (oligo-saccharides); the sialo-mucin is more to the surface and usually deals with microbes, while the sulfo-mucins are in the lower depths of the crypts. We individuals have different antigens that affect the rate at which we degrade the sialo-mucin; furthermore, there is a drop in the number of sialo-mucins when the transformation of colo-rectal cancer occurs. It should be noted that the density of sialo-mucin and sulfo-mucin has differences all along the length of the colon and rectum, with nuances related to gender and can shift their ratios at a site.

There are specific colon bacteria which utilize the sulfate they get from sulfo-mucin; sulfate reducing bacteria use it for their own "respiration" and put out H2S. Yet "normally" sulfate reducing bacteria  are apparently not mostly using the sulfate we add to the colon from our food (this may be because certain  sulfur bacteria varieties, like "normal" desulfovibrio, have a cellular program to interact readily with an oligo-saccharide property of sulfo-mucin in order to take up that sulfate). When there is a shift to depleted sialo-mucin and extra ordinary sulfo-mucin the colon sulfur bacteria population varieties also alters; and certain sulfate reducing bacterial varieties become enriched at the expense of other bacteria.

At which time the colon levels of  bacterial produced H2S can rise and, just like high dietary spin off H2S; this then will depress butyrate's output of H2S  in colonocytes (where any incipient colon cancer's epithelial pheno-type needs to be held in limbo). The natural anti-cancer slow release of H2S from butyrate is then an altered state of high level of H2S in the colon;  with not enough sialo-mucin in the upper portions of colon crypts epithelial cells deeper in the crypt are more vulnerable .

Furthermore, with the shift toward excessive sulfate reducing bacteria (ex: desulfobacter, desulfobolbus and desulfotomaculum as opposed to  "normal" desulfovibrio) , there is the possibility that some cancer cell lines will use that bacterial supplied H2S to more readily morph into their mesenchymal pheno-type. This would be due to H2S impairing certain coloncyte cell line's DNA repair so that there is then damage to the original genome. For details see Mol Cancer Res 2006;4(1):9-14 "Evidence that H2S is a Genotoxic Agent"  complete text at http://
mcr.aacrjournals.org/content/4/1/9.full

To Greensleeves  (Server blocking where belongs),
You might enjoy this all sourdough rye study "Structural diff. btwn. Rye & wheat ...lower post-prandial insulin ..." in 2003 Am J Clin Nutri; 78(5):957-964 full text http://www.ajcn.org/content/78/5/957.full

And 2009 "Endosperm & whole grain rye breads ... beneficial blood glucose profile" in Nutrition Journal 2009, 8:42 full text http://www.biomedcentral.com/content/pdf/1475-2891-8-42.pdf

Thought this interesting, talking about wheat, saw yesterday on the news that NBC is hosting "health week" this week.  It is sponsored by General Mills, if I remember correctly, with emphasis on the importance of eating whole wheat for good health.

1. Should I continue to take all my supplements and medications during fasting, e.g. Niacin, or does it depend?
2. If upon fasting, satiety comes after eating a small amount of food, how do I make sure my nutrition is sufficient to maintain the muscle mass? How do you combine fasting and exercise?

Gene, my guess is that you can't. Or shouldn't. But then you're probably not going to fast for more than a few days at most, so going without exercise for a few days is probably not going to cost you any muscle mass.

I would also think it's probably okay to take your usual supplements, too.  Medicines may be a problem, depending on what they are.  People with serious health issues probably should avoid fasting altogether, unless under the close supervision of his or her doctor.

I'm interested in hearing what Dr. Davis has to say regarding fasting.  Hurry up doc!

Joe

Is it true that fasting can also improve LP(a)?

Agreed Dr. Davis.

I am a big fan of intermittent fasting.... looking forward to more posts.

I've had a similar experience to your post-fast feeling upon eating by doing a 2 or 3 day liquid-only diet that's heavy on water and includes a large protein shake each day.  It's as though you have to periodically remind the part of your brain that listens to the stomach what "full" means.

Like the others, I'm very interested in what the doc has to say in the next article in this series!

To what extent does a person with impaired adrenal and/or thyroid function need to be careful when fasting or low-carbing?

Type 1 diabetic for 40 years, and nowadays I eat about a thousand-calorie high-fat breakfast and a similar dinner.  I rarely eat lunch, and skipping breakfast (simply omit the pre-meal shot of insulin) as well is usually not a big deal any more: I do it occasionally.  Control of blood sugar is much easier now, and Hb A1c around 6 rather than over 10: still room for improvement.  When I was eating skimmed milk with Grape-Nuts or Uncle Sam (whole wheat flakes with whole flaxseed) for breakfast I would have blood sugars as high as 300 by mid-morning and a powerful hunger by lunchtime.  Whatever benefits fasting may have, I find it a lot easier now than it once was, and plan to try it more often, as I'm still overweight.

Is snacking on raw green vegetables between meals also considered grazing?

I experimented with intermittent fasting (IF) for a little over a year. I first got interested in IF through calorie restriction (CR) -- there were a couple papers suggesting that you could extend lifespan through IF without the CR, which seemed like the perfect combination.

These papers are still quoted on many blogs, but I doubt many have actually read them, since none of them actually show you can increase lifespan without restricting calories. See this post for a more detailed analysis:

http://inhumanexperiment.blogspot.com/2010/05/does-intermittent-fasting-increase.html

Anyhow, I still think there might be benefits for doing intermittent fasting -- though I've also seen some studies showing it might have negative effects as well -- and certainly it seems pretty good for weight loss. When I was on a high-fat, low-carb diet and fasting for 24 hours, then eating for 24 hours, I was the leanest I'd ever been. And that was without trying or counting calories:

http://inhumanexperiment.blogspot.com/2009/08/year-of-intermittent-fasting-adf.html

And one more shameless plug, some tips for those who have trouble going without food for 24 hours (or more):

http://inhumanexperiment.blogspot.com/2010/01/how-to-deal-with-5-most-common.html

Personally, I never went for several days without food. I'm not sure it's needed for weight loss anyway, although it might have other health benefits.

- JLL

Hi, Gene--

Green vegetables have no discernible postprandial chylomicron/VLDL consequence and is the exception. I'd consider that safe "grazing."

We usually hold niacin during a fast due to the fluid struggles, which can magnify the hot "flush." We usually continue the other supplements, however.

Hi, Paul--

If not yet corrected, I don't think it would be a good time to fast, since you could feel pretty crumby during your fast.

Fasting should be a positive experience, not something to endure. I'd wait until these issues are corrected.

Hi, JLL--

Agreed. In fact, I believe that the greatest benefits of intermittent fasting are the subjective benefits of reawakened taste and appreciation of food, rather than the physiologic benefits. Nonetheless, it makes sense that, since atherosclerosis and arterial dysfunction are to a large degree postprandial phenomena, prolonged "no-prandial" periods might facilitate arterial health.

Is it possible that current wheat strains have been selected or genetically engineered to be addictive?

Today's Urban Dictionary Word of the Day: Carb Coma -- The sleepy feeling after eating a large meal comprised chiefly of carbohydrates, whether in the form of rice, noodles, bread or dough.  "Dude, I was totally dozing at the office after that giant serving of chow mein for lunch. Total carb coma."

I have been following Fast-5 for three years, and quickly got down to a healthy weight. I'm 58 years old and lost 25 lbs to get down to 160lb (5'-11''), and a reasonable BMI. I fast daily for 19 to 21 hours with absolutely no effort required - it is just the way I live now. During this whole time I have made no effort to restrict wheat in any way. I don't eat a lot of wheat and I don't eat it every day, but on the day after pigging out on pizza I have no trouble with my fasting. There's your black swan.

Ketone metabolites from Beta oxidation of fatty acid, B-hydroxy-butyrate , increase when fasting;  these metabolites act on visceral fat receptor HM74A. The result is upregulation of the anti-inflammatory  molecule adiponectin;  it (adiponectin)  also keeps less glycerols  (think of tri-glyceride group).

The increased adiponectin upshot is the white visceral adipose (not subcutaneous fat) does less lypo-lysis (fat cleaving) and there is a reduced level of free fatty acids going into circulation.  This relief, from excessive "freed" fatty acids ,  permits the response to insulin to improve (ie: sensitivity to insulin better) when go back to eating;  and the longer the fast went on for  the longer the boost of circulating adipinectins stays  around   than before.

Low serum adiponectin levels are common in the obese, hyper-glycaemic,  diabetic;  individuals with  hyper-triglycerides, coronary artery disease (and often even the children of  hyper-tensives.  Metabolic syndrome tends to low adiponectin and concurrent high levesls of circulating triglycerides.

The  actual anti-inflammatory action of adiponectin is a major  part of why the fast makes the body feel so much better;  the digestive  organ rest is given too much focus.   Many individuals report  " pain gone"  from diets  that favor more ketone derived energy
production (like low carb,  calorie restriction &/or  ferments for gut bacteria) ;  because,  there too, the metabolite Beta hydroxy-butyrate is instigating more circulating adiponectin that  then stymies pro-inflammatory cytokines.

Hi, Might--

You make a crucial point that, I believe, explains much of the benefits to fasting: via improvements in cytokine levels and tissue responsiveness, especially adiponectin.

Fabulous!

Hi, Curtis--

Exactly. There are going to be exceptions. However, I speak for the 80% or more people who do indeed have addictive and appetite-increasing relationships with wheat.

I wasn't able to fast when Dr. Davis started discussing it about 1-2 years ago. Most of my life, if I didn't "graze", I'd get hypoglycemic symptoms like my mother, and my paternal grandmother. My mother even got a note from my doctor that I had to have a sandwich before Jr high band practice, else I'd get headaches or light-headed - that's how long I've dealt with frequent hypoglycemia episodes.

So I came up with my own personal mini-fast-challenge. I would only eat when an actual hypoglycemic symptom happened, ignoring the regular hunger pangs. Then when I ate, I avoided sugars, starch and wheat - I did have a bit of rice though. I'm guessing it was about 3-4 days before I could go 5-6 hours with no hypoglycemic symptoms, and about 10'ish days before I could go 12 waking hours with no calories (I draink tea with stevia).

Looking back, both my parents' families ate lots of wheat: bread, biscuits, pasta, so that's probably what gave my paternal grandmother, mother, and then me our hypoglycemia. If I have a hypoglycemic symptom, I start my mini-fast-challenge again. I finally figured out my family's curse is wheat, so I avoid it except the occasional pasta dish.

I followed the "East Stop Eat" approach a while back, with good results. I agree with one poster that said best to skip the breakfast insulin surge. In fact I think the whole "three square meals" with grazing in between, needs to be challenged (perhaps one meal a day). My guess is that humans are designed to go days without food and have plenty of energy. Its an ability that needs to be regained. Also I gather fasting is good for HGH response, especially if combined with resistance training.

Dr. Davis, I have done intermittent fasting for a long time...so long, I have lost count but I think that it has been 4 years. I do my version on a daily basis so it I am not as strict as someone who does this occasionally. Now that being said, my final meal of the day is the meal that I begin my fast so I keep it as nutritious and ketogenic as possible. So, I eat my final meal at around 7:00 P.M. I don't eat again until 3:00 P.M. the following day. Eating is such a treat and I eat very tasty low carb food when I break my fast. I will have my morning coffee with heavy whipping cream and MCT oil. Or I will have a glass of water with MCT oil. I take my vitamin D at this time of day because it wards off any allergy bugs lurking in the air. This summer I would like to lose 10 lbs so I will just kick up my fasting method in intensify my diet by keeping it balanced between protein and fats.

I am not athletic in the least but I find that being active is not hindered during fasting. I strongly believe that we should not need to eat before exercise. Nor should we need to eat immediately after exercise.

Sorry, I just noticed that post came up under my husband's name. That post on fasting should come up under my name Mary...I am the one playing flute.

Yes, I do agree with you . I read about HGH becoming activated through a combination of fasting and resistance training.

Yes it’s true that to become faster and sharper than we should have wheat, grain, etc. in our daily meal than you will be satisfied by your performance.
Physical Therapy Supplies

18 hour fasts are easy, 24 hour fasts are hard, but once I break the 24 hour barrier, another 12-16 hours isn't bad.  My diet isn't wheat heavy, but I certainly don't avoid it.  What works for me is moderate physical activity, which gets me over the hump.  The hump may be the switchover from carb burning to fat burning, which moderate activity of a couple hours duration trains the body to do.

I was quite sold on IF but keep finding conflicting findings, any comments on this http://chriskresser.com/blog/intermittent-fasting-cortisol-and-blood-sugar/ ?

Dr. Davis,
Please refer me to your source of  "wheat is destructive".  I have eaten Shredded Wheat breakfast cereal every day for 25 years.  It is the only breakfast cereal I am not allergic/sensitive to.  After eating it for breakfast, it fills me up and I do not eat again for 6 hours.  I understand about wheat products raising a person's glycemic index, but I have read that the fiber in Shredded Wheat takes so long to digest that it actually controls a person's blood sugar all day.
I am a healthy, near ideal-weight 50 year-old female.  My experience finds this statement to be false: "wheat is a powerful appetite stimulant through its 2-hour cycle of exaggerated glycemia followed by a glucose low, along with its addictive exorphin effect".
Thank you for your time.

I take omega-3 fish oil supplements and I eat lots of oily fish, generally around 400g salmon, 200g sardines and 200g trout per week. I'm not worried about the mercury content of the fish I eat, partly because these are fish low in mercury anyway but also because I did a fair bit of research and discovered that a lot of the mercury content of fish and how it affects a person depends on the age of the person and how many years they have been eating fish. I, for example, only started to eat fish a couple of years ago in my early 50s, and by the time any serious level of mercury might have built up in my body I will be an extremely old lady...but I'm not worried.

I've also read that the mercury in the bodies of children growing up in the Pacific who eat a lot of fish is much higher than the rest of the world but they are not damaged by it, and the beneficial effects of the fish outweigh the effects of the mercury. Here's one comment about that:  'Mercury, fish and you: what to do ?': http://tinyurl.com/5ddkbs

Anne

I have been increasing the amount of salmon in my diet, but it is getting harder to find wild salmon in my area (Tulsa, Oklahoma), and when I do find it, it is much higher in price than farmed salmon. So, as a result, I eat a lot of farmed salmon, which probably does not offer much of a health benefit.

Are there good quality large scale studies linking the use of fish oil capsules with improved outcomes?

Studies like the Japanese one you cited are of people eating fish, not taking the oil separately, and it's worth noting that the Japanese who are always cited as the good health example for fish do eat shark and just about anything else that swims.

It is also a fact that the people I mentioned who needed chelation therapy for proven mercury poisoning were eating mostly salmon and cod.

I do use fish oil capsules. But so many nutrients have proven ineffective when taken apart from the foods they are embedded in that one has to wonder.

Vitamins A, C and E supplementation has not tested out but foods high in those nutrients do.

So that makes me wonder how much of the benefit of eating fish is from the oil and how much from  other factors associated with fish eating. Has the benefit of fish oil eaten without the rest of the fish and not as part of a meal been shown in high quality research not funded by fish oil merchants?

What you want is molecularly distilled fish oil.  The molecular distillation process reduces the amount of mercury to a level that is not detectable with modern instrumentation.  Since our bodies can tolerate detectable quantities of mercury without harm, using molecularly distilled fish oil is pretty much mercury free.

So which brands use molecular distillation?  Carlson's, LEF, and pretty much all of the major brands do.  If you're not sure, take a look at the label.  It should be written somewhere on there.

Any product claiming to have "lower mercury levels" than other quality sources is just blowing smoke.  None of them contain measurable amounts of mercury.

Is rancidity a significant problem with capsules?

The omega-3 fish oil I take is not in capsule form but a liquid - Eskimo-3. It says it has been purified so that mercury and other environmental contaminants are well below current acceptable levels and this has been confirmed by independent studies. It has not been chemically modified. You have to store it in the fridge once opened. They press the oil from sardines caught in deep seas from the Antarctic and south Atlantic.

Anne

the data on mercury toxicity from fish is very interesting- basically, the toxicologist (in lieu of epidemiologists) defined the 'upper limits'. Toxicologists routinely assume 1/10th the level where problems were identified as their upper limit threshold-- if you look at the original data, however, you'll find that it was based on people who's primary food was pilot whale and another group and in both cases there was at best, minimal cognitive changes noted.  they then took this threhold and lowered the limit by 10 fold--- the result of this national public policy--- 3/4 of all pregnant woman eat insufficient amounts of omega3FAs-- had epidemiologist looked at this issue and been involved in creating the recommended guidelines you would have seen 5-10x higher levels of mercury consumption permitted.  i'll find the original data on this and send it your way abit later.

The mercury content of fish oil capsules have little to do with the method of processing and much more with the animal source of oil. Fish oil is generally obtained from sardines, salmon, and cod, all low in mercury. Fish oil capsules are not prepared from swordfish or shark.

I also get these mercury remarks or concerns every time I encourage friends to start taking fish oil supplements. I always explain that as long as they come from clean waters, like the ones surrounding New Zealand, it's ok. I guess I gave them the wrong explanation. Now I know what to tell them.