These so-called short-chain carbohydrates, known as FODMAPs (Fermentable Oligosaccharides, Monosaccharides And Polyols), are difficult for the gut to absorb. Bacteria make them ferment, which is what gives you the bloated feeling and pain, although not the long-term damage linked to coeliac disease.
There are many kinds of FODMAP in many different foods and they disagree with some people more than others. Fructans are in wheat and rye bread but also in garlic and onions. There is excess fructose in pears and honey and sugar polyols in stone fruits and some artificial sweeteners. Another FODMAP is lactose in milk.
The bad news is that if you are sensitive to the FODMAP in wheat-based bread and pasta rather than the gluten, you still need to avoid the wheat-based bread and pasta to relieve your symptoms.
First, I noticed that Friday’s Feedburner email for my blog didn’t list a table of contents at the top like it used to, so if you didn’t happen to scroll to the bottom, you might have missed the post on Nutrient Intakes of SDA Vegetarians. If anyone was feeling a strange emptiness inside this morning, that could be why.
Second, I haven’t asked for support since July! And I haven’t gotten much, either, which lends credence to the age-old saying, “Do not ask and you shall not receive.”
Interestingly, the posts that took the most research were the least popular – I need to stop researching! I’m kidding – as unexciting as the research is to do and to read about, it is a necessary evil.
Thank you for using my Amazon links – they continue to make a difference!
The biggest difference is made by direct donations. Thank you for anything you can give to support this work!
Today was a good day: As longtime readers of this blog will know, I love getting good news about my “bad” habits. 🙂
A study came out that fits in well with past findings, is well-written, and supports my proclivity to eat and recommend soy meats!
It was a report from Adventist Health Study-2 (AHS-2), conducted among caucasian Seventh-day Adventists living in the USA, comparing the intakes of many different foods and hip fracture risk after 5 years of follow-up (1).
First, there was a bit of bad news in that vegans had the highest rates of hip fracture at 3.0 per 1,000 person-years compared to 2.0 for non-vegan vegetarians (including semi-vegetarians) and 1.6 for non-vegetarians. The paper didn’t report whether this finding was statistically significant, but it was not a great trend, obviously. Read on for how to reduce your chances.
Here are findings from the fully adjusted model (2):
– Meat alternatives once a day or more (compared to less than once per week) were associated with a 66% reduced risk of hip fracture in the vegetarians (.34, .12-.95).
– Eating legumes once a day or more (compared to less than once per week) was associated with an 82% reduced risk in non-vegetarians (.18, .06-.54) and an 55% reduced risk in vegetarians (.45, .22-.94).
– Meat more than 3 times per week was associated with a 45% reduced risk in the non-vegetarians (.55, .36-.83), compared to less than once per week.
– Dairy, nuts, soy milk, and “tofu & soy cheese” were not associated with a lower risk. The average amount of tofu & soy cheese per day was only .1 among the vegetarians. They did drink close to a cup of soymilk per day (or “soya milk” as the authors, who apparently think they live in Europe, call it).
The authors emphasize the need for vegans to eat legumes in order to get enough of the essential amino acid lysine:
“[A]n individual who adheres to a vegan diet, which excludes meat and dairy products, will need at least two cups of cooked beans [per day] to meet the recommended lysine intake requirement…Lysine and hydroxylysine are the main amino acids in the cross-linking process of bone collagen…Lysine can also influence bone health through its end product carnitine. Carnitine supplements have been shown to improve bone density in some animal and human studies.”
Note that the requirement for 2 cups of cooked beans assumes no other lysine sources in the diet, which isn’t the case. You can can read more on lysine needs and how to meet them in Protein.
They go on to say:
“Among our participants, intake of meat analogues of at least one serving daily reduced the risk of hip fracture by up to 49%…The main protein ingredients in meat analogues are soya, wheat, gluten, eggs and milk. A typical serving of meat analogues (1 serving ~73 g in AHS-2) contains at least 10 g of protein, but can vary from 9 to 18 g.”
Or 30 g as Tofurky Italian sausage has!
They point out that their finding for meat being protective is backed up by other research but not all. After a brief analysis of the research they suggest that meat intake is associated with bone health when protein intakes are low. And, finally:
“Protein is recognized for its ability to improve [calcium] balance, suppress parathyroid hormone, increase lean body mass and increase production of the bone growth regulator insulin-like growth factor-1.”
This study had something for everyone – low-fat proponents can relish in the findings for legumes and meat alternative eaters can smugly continue in their bad habits!
I have not yet updated the VeganHealth.org article, Calcium and Vitamin D, with this new study yet, but hope to do so in the next few days.
References
1. . Lousuebsakul-Matthews V, Thorpe DL, Knutsen R, Beeson WL, Fraser GE, Knutsen SF. Legumes and meat analogues consumption are associated with hip fracture risk independently of meat intake among Caucasian men and women: the Adventist Health Study-2. Public Health Nutr. 2013 Oct 8:1-11. [Epub ahead of print] | link
2. *Adjusted for fruits and vegetables intake, age, height, weight, gender, energy intake, physical activity, smoking, health status and total calcium intake.
– The nutrient intakes included supplements. However, they also used median amounts (rather than averages) which means someone using a very large dose of a supplement would not skew the “average” intake.
– 45% of the AHS-2 subjects were vegetarian and approximately 8% were strict vegetarians or what I’m calling “vegan.” They eat any category of animal products (meat, fish, eggs, dairy) less than once per month.
– There were two tables of nutrient intakes given in the paper and I used the one that was not adjusted for sex, race, and age as I’m not clear what that actually means in the case of nutrient intakes.
– The lacto-ovo vegetarians ate less dairy protein than the regular meat-eaters (median intake of 7.5 vs. 11.8 g per day). I have seen people suggest that lacto-ovo vegetarians tend to eat a lot more dairy than your average meat-eater, but this shows that is, on average, not the case.
– It was great to see that the median intake of vitamin B12 for vegans was 6.3 µg per day, but there were still many vegans not getting nearly enough as the 5th percentile was at a mere .4 µg per day.
– Calcium intake for the vegans was excellent at 933 mg per day. The 5th percentile was 520 mg. This was much better than the calcium intakes in the bone fracture study from EPIC-Oxford where almost half the vegans were getting less than 525 mg per day (more info).
– Sodium wasn’t terrible at 3,066 mg per day, but would ideally not be over 2,300.
– It looks like vegans ate as many calories as the regular meat-eaters. That’s hard for me to believe and could be an error in the methodology. Or, perhaps, the vegans really did eat as many calories, but you don’t see that often.
References
1. Rizzo NS, Jaceldo-Siegl K, Sabate J, Fraser GE. Nutrient Profiles of Vegetarian and Nonvegetarian Dietary Patterns. J Acad Nutr Diet. 2013 Aug 26. [Epub ahead of print] | link
I seem to run about an average of 6 months behind on these ex-vegan stories.
A reader sent me a blog post from Heather of “Run, Hike, Live, Love” and (had a blog?) “Vegans on the Run.” Her post is titled, 10/1/10–4/17/13, and it is about how she gave up a vegan diet to eat fish again due to iron deficiency.
It starts off with Heather running a race, struggling to run 8 minute miles, going to the doctor and finding out she has iron deficiency anemia. That’s no fun. 🙁
After a year of supplementing with iron, Heather was still struggling with her running. She got tested and her serum ferritin was “24 out of a possible 200.” Well, 24 is low, but it’s not really out of a possible 200 – 24 isn’t even considered iron deficient, though it’s close. 50 would be well out of the danger zone. It would be more important to find out what her hemoglobin was.
She then tells a story about how when she was a kid she caught a fish and was horrified at its suffering and went vegetarian. I sympathize because I also started towards vegetarianism after a day of fishing.
Moving along, Heather decides to buy some fish. At this point, she still has my sympathy.
She takes it home with great anxiety but sees her 8 bottles of supplements on her shelf and realizes that “Real nourishment comes from whole foods, not from bottles.” Now she’s losing me.
Heather cooks the fish and in her words, “The first bite was not what I anticipated. It was delicious. I whispered thankful prayers for the life that I was about to consume to maintain my own and let the tears flow….My stomach was raging for over an hour at the unexpected substance….Eventually the nausea subsided and was replaced within a few hours by a strange sensation: Energy. The fog of fatigue I’d been stumbling around in all day subsided as though I’d been hooked up to a caffeine IV. I was soon bustling around the house doing 10 things at once like I used to.”
And in her final paragraph, Heather says, “The one thing I know is that my body and blood do not lie.”
Hmm. Could Heather have absorbed the iron from one serving of fish and within hours produced enough hemoglobin to have a profound increase in energy?
This sort of thing could happen from blood doping. It happens from cocaine. But a serving of fish?
Apparently, taking the hormone erythropoietin, also known as EPO, takes a full week to increase hemoglobin one point.
Either her body does lie or she had something else going on besides iron deficiency as her story is not physiologically plausible if due to iron deficiency.
I wonder if oysters would provide the same amazing burst of energy?
On September 30, Christina Sterbenz had an article on Business Insider, 7 Reasons Why I Refuse To Stop Eating Meat. I’d like to quickly respond to a couple of her reasons.
Iron is the number one reason Sterbenz gives for continuing to eat meat:
“Yes, vegetables contain iron — but not the good kind. Consuming plants gives your body nonheme iron, a version less easily absorbed by the body….Heme iron, the better type, only comes from life forms with hemoglobin, such as red meat, pork, poultry, and fish.”
While it is true iron from meat is more absorbable than from plants, this would only be a problem for people who are prone to iron-deficiency anemia. I have not come across a vegetarian man diagnosed with iron deficiency anemia that I can remember and none have been reported in the studies on vegetarians and iron deficiency. Some vegetarian women are iron deficient but this can be corrected by changing some habits, like eating foods higher in iron combined with vitamin C, and avoiding coffee and tea at meals. But if you are absorbing enough iron (as most vegetarians are), the iron from plants works just as well as the iron from meat.
In fact, while vegetarians normally do not have iron deficiency, they do have lower levels of iron which may reduce their risk of diabetes. And the good type of iron that Sterbenz touts, heme iron, is associated with colon cancer while the iron from plants is not (more information on iron and chronic disease).
Sterbenz writes, “Also, spinach, considered one of the most iron-rich leafy greens, doesn’t have as much as many believe. But we grew to love it after a German chemist made a typo back in the day.”
Spinach is an excellent source of iron with 3 mg per 1/2 cup cooked. A full cup of cooked spinach (not hard at all to eat) meets almost the entire RDA for men (8 mg) and 1/3 the RDA for menstruating women (18 mg).
Sterbenz: “3. Vitamin B12 only comes from animals.”
Actually, B12 only comes from bacteria. But it’s true that only animal foods naturally contain vitamin B12 in any reliable amounts. This hasn’t been a boon for spreading veganism, but it has actually given vegans who supplement better vitamin B12 status than many meat-eaters. Because it’s harder to absorb vitamin B12 from animal products (due to it being attached to proteins) the Institute of Medicine recommends that all people over the age of 50 get half of the RDA for vitamin B12 from fortified foods or supplements (citation). Vegans get the “good” type of vitamin B12. 🙂
Sterbenz then says, “Almost all multi-vitamins contain B12, as well. But recent research suggests vitamins might be useless,” and links to the article, Vitamin pills ‘are useless’, which describes a study that found supplementing with beta-carotene, vitamin E, and vitamin C did not prevent cancer, heart disease or stroke. This is completely different than showing that vitamin B12 supplements are useless. On the contrary, it is well-documented, conclusive, and without controversy in the mainstream medical and nutrition community, that vitamin B12 supplements work at preventing and correcting vitamin B12 deficiency.
“Much of the pro-vegetarian research out there will try to convince you that humans are natural herbivores, that we’re not meant to eat meat. In reality, our digestive characteristics show we’re omnivorous,..”
Finally, something I agree with. But I don’t believe we’re “meant” to eat anything. We evolved eating certain foods (including lots of insects) and now that we are more ethically evolved some of us are moving society away from killing animals for food.
Referring to a picture of oysters, Sternbenz says, “You know you want them too.”
Sterbenz might be surprised to know that, no, we really don’t want them. Rather than wanting them, I think, “You’re going to put that in your mouth and swallow it?”
That said, since Sterbenz says she cares about animals, I hope she will experiment with at least replacing more meat with oysters! Since she can stomach them, and apparently loves to eat them, she could help prevent animal suffering by eating oysters instead of pigs, cows, and chickens.
Even better, eat some spinach for iron, and try a nice juicy Tofurky sausage for protein and fat. I know meat-eaters don’t think it’s the same thing, but it’s pretty close and without the entrails.
There are a number of different types of people with genetically low LDL cholesterol levels, which normally results in somewhat lower total cholesterol (much lower in some individuals) and much less heart disease. Whether these people suffer from depression, stroke, failure to thrive, or low steroid hormones cannot necessarily be extrapolated to people who have very low cholesterol due only to diet. I also don’t know that rates of these conditions have been measured in such people (none were in the studies below), though there apparently hasn’t been an alarming amount.
It is my understanding that the people with familial hypolipoproteinemia have an inability to produce the protein fraction of the LDL, not the cholesterol portion. They definitely have less cholesterol in their blood, but this doesn’t mean they have less cholesterol in their tissues. Whereas someone with very low cholesterol in their blood due to diet might have lower cholesterol levels in their tissues.
Some readers sent me links to show that people with genetically low LDL levels have longer life spans. I checked out all the links, and followed some of them even further. Unfortunately, none answered the questions I have, but I found the information interesting enough to pass on.
PCSK9 Genetic Variant
People with a mutation in the PCSK9 gene were followed for 15 years in the Atherosclerosis Risk in Communities study from the USA (1). There are at least two variants of this mutation and in the study, 2.6% of black people had one variant that lowered their LDL cholesterol levels by 26% and their risk of heart disease by 88%. This roughly lowered their risk of having a coronary event from 1 in 10 to 1 in 100 during the 15-year time interval. Another variant was found in 3.2% of white people and lowered LDL levels 15% and their risk of heart disease by about 50%.
One would think that this reduction in heart disease would lead to a reduction in mortality, but the authors state, “[I]t is not known whether the beneficial effect of decreased LDL cholesterol levels on cardiovascular disease results in an overall reduction in mortality rates.” Interestingly, the average total cholesterol of the white people with the genetic variant was a whopping 194 mg/dl. For the black people it was 172 mg/dl.
Familial Hypolipoproteinemia
One reader sent me some links to articles on people with familial hypolipoproteinemia which results in very low LDL levels. Here is a run down of the papers:
Steinberg D, Glass CK, Witztum JL. Evidence mandating earlier and more aggressive treatment of hypercholesterolemia. Circulation. 2008 Aug 5;118(6):672-7 (link)
This is a review article that says, “Third, in some kindreds with hypobetalipoproteinemia, LDL cholesterol levels can be < 15 mg/dL throughout life, yet the affected members show perfectly normal growth and development and actually have increased longevity. (40, 41)”
Citation 40, from that quotation directly above, is this paper:
Steinberg D, Grundy SM, Mok HY, Turner JD, Weinstein DB, Brown WV, Albers JJ. Metabolic studies in an unusual case of asymptomatic familial hypobetalipoproteinemia with hypolphalipoproteinemia and fasting chylomicronemia. J Clin Invest. 1979 Jul;64(1):292-301 (link)
It is an article describing one man, age 67, known as “HJB” with an unusual variant of hypobetalipoproteinemia and a total cholesterol level of 47 mg/dl. It doesn’t discuss longevity of such people in general.
Citation 41 is:
Young SG, Bertics SJ, Curtiss LK, Dubois BW, Witztum JL. Genetic analysis of a kindred with familial hypobetalipoproteinemia. Evidence for two separate gene defects: one associated with an abnormal apolipoprotein B species, apolipoprotein B-37; and a second associated with low plasma concentrations of apolipoprotein B-100. J Clin Invest. 1987 Jun;79(6):1842-51 (link)
This paper describes 19 members of HJB’s family (including HJB), whose total cholesterol levels ranged from 31 mg/dl (HJB himself, by this time) to 130 mg/dl, with an average of 84 mg/dl. The only mention of longevity was that HJB was in excellent health at age 75, one of his family members had lived to 95, and one was said to have lived to 105.
Another study passed on by this reader:
Glueck CJ, Kelley W, Gupta A, Fontaine RN, Wang P, Gartside PS. Prospective 10-year evaluation of hypobetalipoproteinemia in a cohort of 772 firefighters and cross-sectional evaluation of hypocholesterolemia in 1,479 men in the National Health and Nutrition Examination Survey I. Metabolism. 1997 Jun;46(6):625-33. (link)
It doesn’t appear to be available in electronic form; so going by the abstract, this study measured the rates of genetically low LDL and total cholesterol levels among male firefighters in Cincinnati. It didn’t measure heart disease or mortality risk.
Finally, in the order they were presented to me, there is a study which actually does appear to suggest that people with familial hypolipoproteinemia live longer:
It was a study of 26 different families with familial hypolipoproteinemia. The abstract says, “Expectation of life for males and females from kindreds with hypobeta lipoproteinemia was 9 and 12 years longer (p less than or equal to 0.002) than that indicated by population statistics for U.S. white populations, whereas expectation of life for males and females from kindreds with hyperalpha lipoproteinemia was 5 and 7 years longer (p less than 0.02).”
This paper was not available online or at my local university library (UC Davis), but I’m hoping to get a copy at some point. And there should be some caution here in suggesting this is proof that genetically low LDL increases life expectancy by 5 to 12 years. Comparing disease rates to the average population does not allow for much adjustment for confounding variables of which there could be many in these 26 families compared to the population at large. But even if such people do have longer life spans, it doesn’t shed much light on the questions I have. As I mentioned in Low Cholesterol: Part 1, I’m not debating whether low LDL prevents heart disease, there is good evidence that it does.
Hunter-Gatherer Populations
The above studies were done on people with genetic mutations, not your average people. The commenter who sent me those studies also said that “Optimal low density lipoprotein is 50 to 70 mg/dl; lower is better and physiologically normal” [my emphasis]. What does “physiologically normal” mean? Read on…it might mean the average cholesterol of people who are very active, eating a diet of about 20% fat.
As evidence, the commenter linked to:
O’Keefe J, Jr, Cordain L, Harris W, Moe R, Vogel R. Optimal low-density lipoprotein is 50 to 70 mg/dl: Lower is better and physiologically normal. J Am Coll Cardiol. 2004;43(11):2142-2146 (link)
This is merely a review article that says, “Evidence from hunter-gatherer populations while they were still following their indigenous lifestyles showed no evidence for atherosclerosis, even in individuals living into the seventh and eighth decades of life (15,16). These populations had total cholesterol levels of 100 to 150 mg/dl…”
Citation 15 from the quotation above is a citation for yet another review:
Cordain L, Eaton SB, Miller JB, Mann N, Hill K. The paradoxical nature of hunter-gatherer diets: meat-based, yet non-atherogenic. Eur J Clin Nutr. 2002 Mar;56 Suppl 1:S42-52 (link)
It says:
“Over the past 64y, anthropological research has consistently demonstrated relatively low serum cholesterol and triacylglycerol levels among indigenous populations that derive the majority of their diet from animal products (Bang & Dyerberg, 1980; Biss et al, 1971; Corcoran & Rabinowitch, 1937; Day et al, 1976; Eaton et al, 1988a; Leonard et al, 1994; Scott et al, 1958; Shaper et al, 1961; Wilber & Levine, 1950).”
I obtained two papers from this list (and could find no abstract for a third, Bang & Dyerberg):
Biss K, Ho KJ, Mikkelson B, Lewis L, Taylor CB. Some unique biologic characteristics of the Masai of East Africa. N Engl J Med. 1971 Apr 1;284(13):694-9 (link)
The Masai, an East African Tribe that had intermingled very little with other African tribes, had a very interesting diet (when this paper was published). They ate mostly milk, 3 – 5 liters per day. They also ate cow’s blood, and the meat of cattle, goats, and sheep. Yet their cholesterol levels were very low, an average of 135 mg/dl. How did they do it?
The authors of the study did an experiment in which they challenged some of the Masai with 2,000 mg of cholesterol per day for 8 weeks! They did not have higher levels of cholesterol excretion (or lower absorption) but rather showed an impressive ability to decrease their internal cholesterol production in the face of eating such high amounts. Autopsies of some of the Masai showed them to have a “paucity of atherosclerosis.”
In other ways, the Masai are (or were) not doing so well with high rates of malaria and tuberculosis.
I don’t think the Masai’s situation can shed much light on what normal physiological cholesterol levels would be for people not in their genetic situation. I didn’t bother looking up the older citations from Cordain et al, but did check out the one from 1994:
Leonard WR, Crawford MH, Comuzzie AG & Sukernik RI (1994): Correlates of low serum lipid levels among the Evenki herders of Siberia. Am. J. Hum. Biol. 6, 329 – 338 (link
The Evenki had an average total cholesterol level of 139 mg/dl for men and 148 mg/dl for women. Despite eating large amounts of animal products, their diets were only 18-19% fat.
The researchers thought that the Evenki’s low cholesterol levels were primarily due to their high activity; the men were more active in herding than the women, cholesterol increased with age in the men only, and the men who lived in the village rather than the herding areas had higher levels. The differences in cholesterol levels could not be explained only by differences in body weight.
The authors said, “Among the African pastoral groups, only the Masai have lower total cholesterol levels than the Evenki.” Longevity and heart disease were not mentioned. Unlike the Masai, the Evenki do not appear to have a genetic propensity for keeping cholesterol low (though this cannot be ruled out).
Interestingly, Cordain also says:
“For the majority (53% n=122) of the world’s foraging cultures the dietary fat intake would lie between 36 and 43% of total energy (Cordain et al, 2000a), values not dissimilar from current Western intakes (McDowell et al, 1994). Despite this dietary characteristic, the available evidence suggests that hunter-gatherers were generally free of the signs and symptoms of [cardiovascular disease].”
I didn’t track down the citations for that statement.
Citation 16 from O’Keefe (above) is to another paper by Cordain and I decided not to track down any more of Cordain’s references as this was taking too much time and shedding very little light on my question of whether a cholesterol of ≤100 mg/dl, caused by diet and not genetic variants, could result in some vegans not thriving.
I have not answered the question about low cholesterol levels (from diet) and steroid hormone production. None of the studies I reviewed in these posts addressed those questions and I hope to look into it more after going through the backlog of other studies I intend to post about.
I don’t mean to dig my heels in and be hyper-skeptical, but I just don’t think these populations exclude the possibilities of very low cholesterol being a problem in failure to thrive for some people.
References
1. Cohen JC, Boerwinkle E, Mosley TH Jr, Hobbs HH. Sequence variations in PCSK9, low LDL, and protection against coronary heart disease. N Engl J Med. 2006 Mar 23;354(12):1264-72. | link
It’s been so long since I wrote anything, some of you might have been wondering if I had died from low cholesterol. No, I am still here plugging away. But unlike Dr. Michael Greger, whose Latest in Clinical Nutrition: Volume 15 is now out on DVD, I have not been working at a speed that violates Einstein’s theory of relativity.
My post of August 28th, The Winter of Their Discontent, caused quite a firestorm of comments. (Whoops! – I mean it was correlated with a firestorm of comments.) Let’s just say that some people do not care for the suggestion that cholesterol levels could get too low.
I’ve spent much of my nutrition time over the last few weeks checking out links to studies that people posted in their comments, along with many others that I found along the way, and want to share what I have found. But first, I want to clarify a few things.
The question I am trying to answer is: at what point, if any, does total cholesterol become so low that it could impact things such as steroid hormone production or mood in some people? And as a corollary: Is low cholesterol possibly a culprit when it comes to the egg cravings some vegans get?
One thing I have never said, and am not suggesting, is that low LDL cholesterol levels don’t protect against atherosclerosis (or even mortality) and I’m not sure why people have jumped to the conclusion that I am implying this.
Unfortunately, I have not done a good job of documenting the anecdotal reports of vegans who have come to me with problems who also have very low cholesterol. One guy was passing out unless he ate cheese, and his cholesterol levels were about 100 mg/dl. My recollection is that adding plant saturated fat didn’t help him. A few other people have had loss of libido which improved upon adding coconut oil (I don’t know what their cholesterol levels were). Another person with cholesterol of 94 mg/dl was suffering from mild fatigue, headaches, and anxiety. Kristen, the ex-vegan featured in The Winter of Their Discontent, had an irregular menstrual cycle (among other things) and a cholesterol of 95 mg/dl. However, I also know vegans with cholesterol levels below 100 mg/dl who appear to be thriving.
So what do we know about low cholesterol?
Low Cholesterol and Hemorrhagic Stroke
During the 1990s, it became known that cholesterol was associated with mortality in a U-shaped curve. In other words, both high and low cholesterol levels were associated with higher mortality – though much more on the high cholesterol end. At the time, the thinking was that most of the association of higher mortality with low cholesterol was a merely a manifestation of early cancer, poor nutrition from depression, or liver disease and poor nutrition from alcoholism. The remaining cause of increased mortality was thought to be due to an increase in risk for hemorrhagic stroke (which is a much less prevalent form of stroke than the more typical ischemic stroke where a blood vessel to the brain is blocked).
The most recent, comprehensive review I found on low cholesterol and hemorrhagic stroke was a 2013 meta-analysis of prospective studies (1). Among 17 studies, they found that high total cholesterol was associated with a 31% decreased risk of hemorrhagic stroke (.69, 0.59–0.81), although publication bias was detected. The vast majority of these studies adjusted their results for blood pressure and alcohol intake, among other variables. Lower LDL, but not lower HDL, was also associated with an increased risk of stroke.
It should be noted that lowering one’s LDL decreases heart disease risk by so much that you are better off with a low LDL even if it does increase the risk for hemorrhagic stroke. It is also still possible that these studies had confounding variables that could not be fully adjusted.
The authors finish their paper by saying, “Our results remind clinicians to take this caution during intensive lipid-lowering therapy. Further studies are needed to investigate the underlying pathogenesis better, and identify subjects who would benefit most from lowering cholesterol without risk of hemorrhagic stroke.”
With few exceptions, the low cholesterol category was less than about 150 mg/dl; the average cholesterol in the lowest categories was rarely given. I have not taken the time to read each study and see if there is any way to detect trends as to whether the findings were different based on the different cholesterol levels being compared or the level or types of adjustments.
A reader pointed out a study from Korea (2), which was included in the 2013 meta-analysis (1), in which the risk of hemorrhagic stroke disappeared after adjusting for blood pressure.
There were 8,319 people in the lowest cholesterol category of 130 mg/dl or less (average cholesterol not given). The decreased risk of having a hemorrhagic stroke in the fully adjusted model (including blood pressure and alcohol consumption) for every 38.6 mg/dl (1 mmol/l) increase in total cholesterol was 9% (.91, .87-.95).
However, when they broke the cohort into two groups, those with high blood pressure and those with normal blood pressure, the effect did not hold for those with normal blood pressure. There was still a non-significant trend towards lower stroke in those with “medium” cholesterol levels as compared to the lowest category.
They broke the group up even further. Among those with high blood pressure, they stratified the results for gamma glutamyl transferase (GGT) which reflects alcohol consumption. At low concentrations of GGT, low cholesterol was not associated with a higher risk of hemorrhagic stroke among those with high blood pressure.
The researchers conclude, “In effect, low blood cholesterol may act as a marker of the health damaging effects of alcohol, rather than be a cause of hemorrhagic stroke.”
Based on the results from the 2013 meta-analysis, I’m not sure that this one study from Korea can be considered to put to rest the entire question of whether low cholesterol, in itself, can contribute to hemorrhagic stroke. Apparently the authors of the meta-analysis didn’t think so, but I’m actually inclined to think perhaps it does.
In any case, if you have low cholesterol (below 150 mg/dl) and have either high blood pressure or drink alcohol heavily, you should talk to a doctor about your risk for hemorrhagic stroke.
Low Cholesterol and Depression
The most recent, comprehensive report I found was a 2008 review from the journal, Psychiatry (3). They sum up their findings nicely in the introduction:
“A number of investigators have found a possible relationship between low serum cholesterol levels and mood disorders. In addition, low serum cholesterol levels have been associated with suicidal ideation [suicidal thoughts] and suicide attempts. While the pathophysiology of this association remains unknown, some researchers have postulated that there may be a relationship between altered lipid metabolism and changes in serotonin functioning. In addition, some researchers have found that the pharmacological treatment of depression results in increased serum cholesterol levels. While controversies and inconsistencies characterize this area of study, it appears reasonable to conclude the following: (a) alterations in lipid metabolism may be one of several risk factors for the subsequent development of depression and/or suicidal ideation/suicide attempts (i.e., a non-specific contributory variable) and/or (b) low serum cholesterol levels are an inconsistent but possible biological marker for the manifestation of these phenomena in some individuals.”
In other words, low cholesterol might cause depression and suicidal thoughts/attempts in some individuals. Could this be related to why some ex-vegans claim their mood became much improved upon going back to eating animal products?
More research is needed. Stay tuned for Part II (now available).
References
1. Wang X, Dong Y, Qi X, Huang C, Hou L. Cholesterol levels and risk of hemorrhagic stroke: a systematic review and meta-analysis. Stroke. 2013 Jul;44(7):1833-9. doi: 10.1161/STROKEAHA.113.001326. Epub 2013 May 23. | link
2. Ebrahim S, Sung J, Song YM, Ferrer RL, Lawlor DA, Davey Smith G. Serum cholesterol, haemorrhagic stroke, ischaemic stroke, and myocardial infarction: Korean national health system prospective cohort study. BMJ. 2006 Jul 1;333(7557):22. Epub 2006 Jun 6. Erratum in: BMJ. 2006 Sep 2;333(7566):468. | link
3. Sansone RA. Cholesterol quandaries: relationship to depression and the suicidal experience. Psychiatry (Edgmont). 2008 Mar;5(3):22-34. | link
In May, a cross-sectional study from Germany was released, comparing the teeth and gum health of vegetarians (89 lacto-ovo, 11 vegans) to 100 non-vegetarians (1).
Among the exclusion criteria was “systemic diseases that negatively influence periodontal conditions (for example, diabetes mellitus…).” Because vegetarians have much lower rates of diabetes, that exclusion criteria could negate the capacity for this study to actually describe differences between vegetarians and non-vegetarians. There was also no information regarding from where they recruited the vegetarians and how anti-mainstream dental care they might be. They did find that the vegetarians in the study went to the dentist less.
The authors’ summary:
“A vegetarian diet or vegetarian lifestyle, respectively, has a positive effect on periodontal conditions. Vegetarians show less inflammation signs, less periodontal damage, less [missing teeth] and as a result of a better dental home care reveal better plaque scores. In addition, vegetarians have a higher level of education. However, regarding the dental conditions, vegetarians show more [decayed teeth] and more erosion.”
To put this in some perspective, the vegetarians averaged .98 teeth with erosion while the non-vegetarians averaged .40.
I would not take this study to mean anything for any given person’s dental health. As far as a vegan diet goes, make sure you get enough calcium and vitamin D. I personally get regular dental check-ups and use a toothpaste with fluoride. Be careful of eating too much dried fruit.
For more info on the German study, here is an article from the Dental Tribune (thanks, Dima):
I realize it’s currently summer. But someone forwarded to me the post of yet another ex-vegan food blogger who divulged to the world this past winter that she was giving up the vegan diet. This time it was Kristen of KristenRaw.com in her post of March 17, 2013, My Vegan Diet Caused Health Problems. Would Primal, Paleo, Or “Real Food” Be Better?
A few paragraphs in, Kristen lists a couple of common threads that she has noticed among the meat-curious vegans:
“We were vegan, some quite smugly, thinking it was the human ideal of a smart-n-healthy diet, but then, only after several years, started to experience health problems, and then switched back to omnivore, and the health problems disappeared….What we also have in common — made somewhat easy no doubt due to having adapted to a strict (vegan) diet for many years — are the strict kinds of omnivore foods we eat now vs what we were eating pre-vegan….Even more so for former raw fooders, whose restrictions (such as avoiding grains) make some vegans’ diets look like junk food.”
Kristen’s story is the typical one – she became vegan for animal rights reasons and at first she did great on the vegan diet and got into raw foodism, etc. After a few years she started to not feel so well, she tried everything to make it better, she went back to eating animal products and within hours she started to have a miraculous turn around in her health.
She originally tried to counter her health problems with, “superfoods, fancy juicers, superherbs, tonic herbs, prepping foods various ways to optimize nutrients, following rules for combining or not combining certain foods like having vitamin c with iron rich plants – just to name a few….”
Although there isn’t much to indicate that Kristen was suffering from iron deficiency, I’m impressed with her attempt to add vitamin C to meals with iron rich plants which is scientifically based. In terms of the rest of her attempts to reclaim her health, if only she knew about all the vegans who are not failing, who she might describe as “junk food vegans.”
At one point, Kristen’s cholesterol was measured at 95 mg/dl. Her animal food cravings started out with “dreams of eggs.” Craving eggs seems to be a common theme, and I take the egg cravings as a possible sign of nutrient deficiency for a few reasons. One, eggs are fairly disgusting, especially if you haven’t eaten them in a long time and don’t happen to be craving them. If someone said they were craving Häagen-Dazs, I’d be skeptical of a nutritional basis. KFC? Might be the 11 herbs and spices. But eggs? Something must going on here.
To sum up the situation, we have someone with very low cholesterol at 95 mg/dl craving one of the main sources of cholesterol, eggs. And after eating animal products, she quickly started to feel better. Following Occam’s razor, it seems to me a safe bet that she was craving eggs because her body needed cholesterol and she improved so quickly because she got an immediate boost from it.
Admittedly, I don’t know for certain if this is what is going on. Eggs are also high in choline and sulfur. And perhaps people just cannot crave what they need and these cravings are the brain misfiring. But, in my humble opinion, the evidence is mounting to implicate low cholesterol in many of these cases of failed raw foods/whole foods vegans.
Here are links to the previous posts on ex-vegans:
