A. Does flax contain phytoestrogens? Yes.  In fact, flax seeds are a more potent source of phytoestrogens than soybeans. Is the ground flax causing your symptoms? Hard to say.

The whole issue of phytoestrogens (estrogen-like compounds found in plant sources including soy and flax) continues to bedevil researchers. Do they block the effects of estrogen, thereby protecting against things like breast cancer? Or, do they exert weak estrogenic effects, thereby protecting against things like heart disease and osteoporosis? Both? Sometimes one and sometimes the other?

Despite copious research, we still don't have a definitive answer on how phytoestrogens behave in the human body and why.  

Searching for clues in a sea of conflicting and confounding information, it appears that phytoestrogens probably don't do much for hot flashes but may help preserve bone density and reduce risk of heart disease.  The findings on cancer are even less conclusive. Phytoestrogens may protect some people against cancer,  but those with hormone-sensitive cancers are usually advised to avoid them. 

I have fewer concerns about whole foods like flaxseed and soybeans than I do about supplements which extract, isolate, and concentrate the bioactive compounds.

Returning to your question: I don't know if your symptoms are due to "estrogen dominance" or not. But the easiest way to find out whether flaxseed is contributing to them might be to stop eating flax for several weeks (try to keep everything else about your diet the same) and see if you notice any improvement.

A.   Sourdough starter does contain lactobacillus bacteria, often referred to as probiotics. It's the lactobacillus that give sourdough its characteristic sour flavor. But it's hard to say for sure which strains are present in a sourdough without laboratory analysis. The sourdough in my kitchen probably has different strains than the one in yours, for example. And different strains of lactobacillus offer varying health benefits, as discussed in this recent post on probiotics.

But whatever beneficial bacteria may be present in your sourdough starter, they will probably be destroyed by cooking. Most lactobacillus bacteria are only viable to about 112 degrees F.  So while sourdough starter could be considered a probiotic food, sourdough bread would not.

Another potential health benefit of sourdough is that the bacteria partially "digest" some of the starches and sugars in the grains.  As a result, sourdough bread appears to cause less of an increase in blood sugar than yeast breads. (Here's a link to the study.)

In terms of the relative nutritional value of sourdough, the biggest factor is probably whether it's made with refined or whole-grain flour. And, although whole-grain sourdough may be healthier than regular white bread, it is still basically bread. I wouldn't eat it in unlimited quantities!

For more on the science of sourdough, see this article.

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As a nutritionist, I've worked with patients who fail to lose weight even when their food diaries show that they are being diligent about their diets.  They assure me that they are accounting for every bite of food and correctly estimating portion sizes.  They're convinced that a faulty metabolism makes it impossible for them to lose weight.

Yet a recent study suggests another possibility. In a 12-month weight maintenance study (other details of which are being discussed in this recent post), the subjects kept diet diaries, which were examined by the researchers at regular intervals. However, the researchers report that "it was apparent that, on average, women in both study groups had underestimated their food intake."

And not by a little bit.  On average, the women reported having consumed 1370 calories per day.  The researchers calculated that their actual calorie intake was 2044 calories per day. That discrepancy of 674 calories a day adds up to over 5 pounds a month!

The men, on the other hand, were spot on: They reported average intake of 1765 calories, the researchers estimated actual intake at 1771.

Anyone have any theories as to why women would be so much less accurate at recording what they eat, despite the fact that they traditionally do more of the cooking and food shopping and are presumably familiar with the weights and measures involved?

On the other end are those who believe that quality is the key: you can eat as many calories as you want without gaining weight as long as they are the right kind of calories (i.e. protein and fat rather than refined carbohydrates).  

Those in the second camp spend a lot of time talking about how refined carbohydrates stimulate insulin release which promotes fat storage, while protein increases thermogenesis and fat-burning.  But I think the magnitude of these metabolic effects is greatly over-stated. 

I suspect that the real "magic" of the low-refined-carb diet is that it tends to regulate calorie intake.

Refined carbohydrates tend to stimulate appetite and lead to over-consumption. But what if you take appetite out of the equation.  What happens when someone else decides what and how much you eat? Consider this recent study: 

After losing an average of 36 pounds on a weight loss program, obese subjects were put on one of two weight maintenance regimens: one was high protein and the other high in carbs.  A year later, both groups were equally successful in maintaining their weight loss. The researchers concluded that "the protein or carbohydrate content of the diet has no effect on successful weight-loss maintenance."  

When calories and macronutrients are "tightly controlled," the metabolic magic of the low-carb diet is undetectable.  This would seem to support my suspicion: The primary advantage of the low-refined-carb diet is not that it recalibrates the body's metabolism and tendency to store or burn fat, but that it reins in appetite, thereby reducing calorie intake. Nothing wrong with that!

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Media reports are quick to point out that this is just the latest in "an ever increasing list of bad news for red and processed meat."

In all of these studies, the division of meat into "red" and "white" seems totally arbitrary, as I discussed at length in this post: Meat and mortality: What does color have to do with it? 

In this particular case, the authors concede that the apparent association between meat consumption and diabetes risk could be explained by other factors. (So why exactly are we going to press with this result?)

A false association seems even more likely in this case than in the recent associations between meat intake and cancer risk or all-cause mortality.  At least there are plausible mechanisms to explain why high meat intake might increase cancer risk. For example, charred meat contains known carcinogens--although I hasten to point out that this has nothing to do with the "color" of the meat.

Diabetes is a disease of disordered carbohydrate metabolism. Meat is made up of protein and fat. How could eating more protein and fat increase the risk of diabetes?  Doesn't it seem more likely that there is something else about the lifestyle or dietary habits of people who eat large quantities of meat (especially processed meat) that might increase their diabetes risk? Are they also over-weight? Are they sedentary? What's their consumption of alcohol? Of high-glycemic foods? 

I'm keeping an open mind but pending more convincing data, I'm not sure I'm buying it.

There are plenty of compelling reasons to limit kids' intake of sugar. Candy is a source of empty calories that can displace more nutritious foods, lead to weight gain, and wreak havoc with insulin metabolism. (Type 2 diabetes used to be called Adult Onset Diabetes, but no more.)

But many parents are also convinced that sugar turns kids into little monsters--making them hyper-active, aggressive, or otherwise unmanageable. Yet the research fails to bear this out.

Is it all in parents' heads? 

Controlled studies have measured the effects of sugar consumption on behavior and cognitive performance and failed to find any connection. See for example this meta-analysis. There have even been interesting studies where parents were asked to observe kids behavior. When the parents thought the kids had eaten sugar, they reported changes in behavior--even when the kids had actually been given a placebo. See this article for more on the sugar-hyperactivity myth.

Just last month, there was an interesting new twist on this: Researchers found that kids who ate candy every day were more likely to be arrested as adults for crimes involving violence, as reported by AP News. The researchers hastened to add that the association is probably more complex than it sounds. It may be, for example, that individuals with poor impulse control eat more candy as kids and then commit more crimes as adults. 

What's a responsible parent to do?

Most parents settle for damage containment and try to strike a balance between nutrition concerns and letting kids enjoy this once-a-year festival. Rather than banning all Halloween candy (now who's the monster?), try to limit the amount that is collected and then dole it out slowly.  One small treat after a healthy meal isn't going to turn your kids into monsters.  Getting your kids up and moving--whether it's to rake leaves, play touch football, or even some Wii tennis--is also an effective way to mitigate the effects of a little extra sugar.  

And rightfully so.  Any system that considers Froot Loops cereal to be a smart choice is worse than meaningless. Read more here.

A. It's not so much that fat-soluble vitamins dissolve in fat, but that they are carried across the intestinal cell barrier by lipid (fat) molecules.  So, while it is true that fats are necessary for transport and absorption of fat-soluble vitamins, it doesn't take much!

A couple of years ago, there was a study that found that eating avocado with vegetables increased the absorption of fat-soluble beta-carotene from the vegetables. However, a study that looked specifically at vitamin D found that vitamin D was absorbed just as well from both skim milk and orange juice as it was from whole milk. (Maybe the fiber in the vegetables plays a role somehow?)

The most likely causes of fat-soluble vitamin deficiency includea missing or malfunctioning gall bladder, bariatric (weight loss surgery), intestinal resection, or other serious digestive diseases that interfere with absorption of fats.

A little background on the homocysteine hypothesis

Population studies (aka epidemiological studies) showed that people with high levels of homocysteine in their blood had a higher risk of heart disease. Homocysteine is an amino acid which is an normal byproduct of protein metabolism. Ideally, it is further converted into another amino acid, methionine. However, if this "recycling"  breaks down, homocysteine can build up in the blood. 

When the link between high homocysteine and heart disease risk was noticed, researchers theorized that homocysteine might irritate the blood vessel lining, leading to injury, inflammation, and the formation of arterial plaques.

Certain B vitamins (B6, B12, and folic acid) act as co-factors in the conversion of homocysteine to methionine. Further research confirmed that those with high homocysteine tended to be low in one or more of these nutrients. Taking the next step, it was established that supplementing with these nutrients reliably reduced elevated homocysteine levels. It seemed all but certain that this would in turn lower heart disease risk.

Hold that thought

However, the homocysteine hypothesis recently took a big hit, in the form of a meta-analysis of eight studies involving some 24,000 subjects. The upshot? The authors found “no evidence that homocysteine-lowering interventions, in the form of supplements of vitamins B6, B9 or B12, given alone or in combination, at any dosage compared with placebo or standard care, prevents myocardial infarction, stroke, or reduces total mortality in participants at risk or with established cardiovascular disease.”

Ouch.

Those in the business of selling nutritional supplements are crying foul, claiming that the conclusions are "misleading."  Read responses from the Health Food Manufacturers’ Association (HFMA) and the International Alliance of Dietary/Food Supplement Associations (IADSA).

It's possible that those with very high homocysteine levels have more to gain than those with only mildly elevated levels--and that the meta-analysis obscures this reality. The meta-analysis also failed to evaluate whether B vitamins could prevent healthy people from developing heart disease. But, coming from organizations who profit from sale of dietary supplements, I find this argument less compelling.

I'm curious: How many of you have had your homocysteine levels tested? How many of you take B vitamins specifically to manage homocysteine levels? Share your comments below.

A. I think it's a little soon to be thinking about prescription meds for life!!  Given all you've reported here, you may not have anything to worry about.  For one thing, high cholesterol does not mean you have (or will develop) heart disease.  Although elevated cholesterol is statistically linked to a higher incidence of heart disease, many people who die of heart disease have normal cholesterol...and many people with elevated cholesterol never get heart disease.  Cholesterol tests are screening tools, not diagnostic ones.

Cholesterol is only one piece in a larger picture. Given the rest of the details you've given (normal weight, not sedentary, no family history of heart disease or high cholesterol, normal blood pressure), your statistical risk of developing heart disease in the next ten years is extremely small. 

I'm also wondering about the details of your cholesterol--specifically about the break-down of HDL ("good") and LDL ("bad") cholesterol.  Your total cholesterol may be high because your HDL is high, thanks to all your healthy habits.   I would think before prescribing medication, your doctor would follow up with a more comprehensive lipid panel. I'd give even odds that a retest would show normal cholesterol, anyway. The slightly high reading may well have been an anomaly.

Finally, it sounds as if your diet is very low in fat and fairly high in carbohydrates.  If you wanted to see if dietary modifications might nudge your cholesterol numbers in the right direction (although, again, I'm not sure you really have that much to worry about), you might try adjusting the balance of your diet to be a little higher in fat and lower in carbs, particularly grains. Olives, olive oil, almonds, and avocados (all rich in monounsaturated fats) would be good choices.

Let us know what happens next.