Selenium and Weight Gain

Feeling sluggish? Having difficulty losing weight? Or maybe you've been gaining weight without increasing what you eat? You might want to check your supplements. Or your rice if it was grown in selenium-rich soil. In the study I'm about to describe, healthy men who were fed between 200 and 300 micrograms of selenium daily (5 times the RDA, or the amount in a typical supplement) gained weight without increasing their caloric intake.

For years I've written about the risks of consuming too little of this or that nutrient. Lately, I find myself writing more about the risks of consuming too much. What does this say about America in the 21st Century?

Here we go...

The study appeared in the Journal of Nutrition in November 2003. It was funded by the USDA's Agricultural Research Service:

Dietary Selenium Intake Modulates Thyroid Hormone and Energy Metabolism in Men

Methods

Eleven healthy adult men were confined to a metabolic research unit and fed a controlled diet of conventional foods (not supplements) for 120 days. For the first 21 days, all 11 men consumed foods that provided 47 mcg/d selenium (RDA is 55 mcg). For the remaining 99 days, 6 men consumed calorie-equivalent foods that were naturally low in selenium (providing about 14 mcg/d), and 5 men consumed calorie-equivalent foods that were naturally high in selenium (providing about 297 mcg/d).

Results

The men in the high selenium group experienced:

• Decreased levels of selenium-dependant thyroid hormone (T₃).
  
• Increased body weight.
  
• Increased fat mass.

The men in the low selenium group experienced:

• Increased levels of selenium-dependant thyroid hormone (T₃).
  
• Decreased body weight.
  
• Decreased fat mass.

Here are these men's weight changes (To convert kg to lbs, multiply by 2.2.):


The authors speculate:

"... a simple extrapolation suggests that if the effect of high dietary selenium were to persist, it could cause a weight gain of up to 12 kg (26.4 lbs) in 5 years."

A drawback to this study is the small population size: 11 men. However, the study's methods more than made up for the small population size. Unlike the recently-discussed diet study where women reported their intake (and likely fibbed), these men were confined and fed. They were required to walk for 2 miles every day and were prohibited from any other form of exercise. They were under 24-hour supervision. Energy intake and expenditure was meticulously documented. That's control.

Slow, Insidious, and Not Likely to Burden the Healthcare System, at Least in the Beginning

Although the men's thyroid hormone levels changed, they remained within a normal range. These changes would be considered subclinical, and would not necessitate pharmacological action.

A Dab'll Do Ya

Certainly, there's a need to provide adequate selenium. It replenishes the antioxidant enzyme glutathione peroxidase (GP) which is useful in detoxifying acrylamide. You remember acrylamide, don't you? If not, and if you enjoy your bread toasted or your potatoes fried, it might be worth a look, here or here.
________

More Antioxidants in Food

Question: Steam either of these foods and you increase their antioxidant content by over 400%.
Hint: They're both vegetables.


Answer: (Select text above line with your mouse.)
Green peppers or Green cabbage


The above might not come as a surprise to those who recall my post Antioxidants in Food, where I discussed a study that found higher levels of antioxidants in a russet potato after it was baked than before. The same was true for cooked tomatoes.

Since I ended my last post advocating food as the preferred source of antioxidants (over supplements), I felt obliged to name some of the best food sources for these compounds.

The most exhaustive analysis of antioxidants in common foods I could find was published in the July 2006 issue of The American Journal of Clinical Nutrition. Researchers analyzed 1113 food samples:

Content Of Redox-Active Compounds (Ie, Antioxidants) In Foods Consumed In The United States


Processing Increases Antioxidant Content of Certain Foods

Before I get to the top 50 antioxidant-rich foods, I want to share an unexpected finding of this study: many foods actually increase their antioxidant content after being cooked.

I compiled the following table from data in the study. It shows 20 foods that have higher antioxidant levels after being cooked compared to before. (Note cabbage and pepper from question above.) Since these numbers are percents, values below 100 represent a loss of antioxidants after cooking. Only 3 foods in this table fell into that category: rice, spaghetti, and corn grits.

Note: I've been getting emails about the pie crust entry in this "Effect of Processing" table. Let me clarify:

1. This table does not indicate the antioxidant content of foods, only which foods' antioxidant content changes when heated. If you'd like information on the antioxidant content of foods, see the table beneath this one.
   
   
2. In fact, this study's measurement of antioxidants in pie crust is negligible: 0.009 mmol/serving. If the effect of baking increased this amount by, as the table shows, 311% to 1450%, that would still only raise pie crust's antioxidant content to 0.028 mmol to 0.130 mmol/serving. Pie crust is not a good source for antioxidants.

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Top 50

As promised, below is a table of the 50 most antioxidant-rich foods tested in this study, by serving size.*


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* Serving size varies. Below are some that apply to the above table:

• For fresh fruit, a serving was 1 cup.
  
• For walnuts, a serving was 1 oz.
  
• For coffee, a serving was 8 oz. brewed.
  
• For ground cloves, a serving was 1 teaspoon. (I dare you to consume 1 tsp. ground cloves in a sitting.)
  
• For red wine, a serving was 3.5 oz. (That's less than 1/2 cup. Somebody there is a teetotaler.)
  
• For fruit juices, a serving was typically 8 oz.
  
• For vegetables, a serving was typically 1/2 cup.

________Photo by snowcat, from Flicker.

Two-timing Antioxidants

There are times when antioxidants are good. There are times when antioxidants aren't so good, for example, when they quench too many of the free radicals that our bodies use as signaling molecules.

The Case of Selenium and Insulin Resistance

In 2004, McClung et al., conducted a study on mice. Those with above average amounts of a selenium-containing enzyme (glutathione peroxidase: GP), which acts as an antioxidant, had higher rates of insulin resistance, a precursor to diabetes. They were also heavier and had more body fat than control mice. These changes occurred when certain free radicals which are used as signals in insulin function were rendered useless by too much of the antioxidant enzyme GP.

"Most people believe that both selenium and the selenium-containing enzyme GP are good for health by protecting cells and tissues from oxidation. However, this study suggests that they are a double-edged sword. Antioxidants can be harmful by neutralizing too many free radicals and interfering with insulin signaling, which results in promoting obesity, insulin resistance and possibly diabetes."
- Xingen Lei, study author

If you're interested, here's their study (free full access to boot):
Development Of Insulin Resistance And Obesity In Mice Overexpressing Cellular Glutathione Peroxidase

Sidenote: The current RDA for selenium is 55 micrograms/day (55 mcg/d) for men and women. The Tolerable Upper Intake Level (UL) is 400 mcg/d (400 mcg = 0.4 mg). Intakes above the UL may cause adverse effects. (See last paragraph.)

This is one more reason I'm reluctant to champion high-dose antioxidant supplements. However, antioxidants from food are a different story:

1. You get a knock-down array of compounds. Where a pill may contain one carotenoid, e.g. beta-carotene, food contains hundreds of carotenoids - some found to work better when others were present (synergistic effect).
   
2. If you're eating a variety of foods (and a sane number of calories), it's pretty difficult to consume too much of any one nutrient.
   
3. A plateful of food tastes better that a plateful of pills. Forks better too.

Let me close with the story of a woman who experienced supplement-regret:

"Perhaps the most famous example of selenium toxicity was reported in 1984. About 11 days after starting to take supplemental selenium, a 57-year-old female who was otherwise in good health noted marked hair loss which progressed over a two-month period to almost total alopecia. She also noted white horizontal streaking on one fingernail, as well as tenderness and swelling on the fingertips and purulent discharge from the fingernail beds. All of her fingernails eventually became involved and she lost the entire fingernail of the first digit affected. She also experienced episodes of nausea, vomiting, a sour-milk breath odor, and increase in fatigue. She learned a little over three months later that the selenium tablets she had taken were recalled by the distributor because they, in error, contained over 27 milligrams of selenium per tablet, 182 times higher than labeled."
- PDRhealth - Selenium

________Photo: Homegrown

Fear Not The Fat

Continued from my last post ... Women in the diet study professed to be eating about 300 calories/day less than when they started. They also reported increasing their physical activity.  And they all lost weight, no matter what diet they followed.

It's been the case that any weight loss (even small amounts, in this case ~3% across diets) gives rise to an improved cardiovascular disease (CVD) profile. Gardner, et al., looked at this. They "examined the independent effect of diet group on secondary outcomes [HDL, triglycerides, BP, etc.] after adjusting for 12-month changes in weight."

Women in the Atkins group had better HDL, triglyceride, and blood pressure measurements independent of weight loss. It appears that the protein, carbohydrate, and fat proportions of their diet had a beneficial effect on their blood values whether they lost weight or not. (Although weight loss still improved these figures.)

Here are some CVD risk factor changes in these women after a year. Keep in mind that variation was so great, only a few of these changes reached significance, mostly in favor of Atkins.


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* From the study: "Although a higher LDL concentration would appear to be an adverse effect, this may not be the case. ... The triglyceride-lowering effect of a low-carbohydrate diet leads to an increase in LDL particle size, which is known to decrease LDL atherogenicity." ________
This isn't the first study to show that a low-carb diet results in increased HDL (the "good" cholesterol) and decreased triglycerides. But when you lower carbs, you automatically increase fat and protein. And isn't fat the felon? Maybe not.

Perhaps more generous amounts of fat in the diet (recall fat consumption in Atkins eaters relative to the others, last graph in post) might not be as harmful as we are led to believe, if that fat, along with protein, is replacing, not adding to, carbohydrate calories. Even better, if it's replacing highly processed (high glycemic index) carbohydrate calories. (The type of fat we should eat? This study did not elucidate. Although Atkins women were eating about 7g more saturated fat than the other groups.)

There was an emphasis on reducing intake of simple/processed carbohydrates and sugars in all 4 diets. If women abided this, it remains that reducing overall amount of carbohydrate, not just switching to complex carbs (low GI), may benefit CVD outcome. ________ Photo via Free Digital Photos.net.

Diets Are Hard

Dr. Christopher Gardner is one busy researcher.

Remember my post last week about the garlic study? The one that received lots of media attention for its failure to show garlic useful in reducing cholesterol? They used a prepared garlic mash that had been previously frozen and thawed. Maybe fresh would have been different, but the study would have been difficult to conduct and control without some sort of monitored dosing.

Well, The lead author on the garlic study was Dr. Christopher D. Gardner of Stanford University. And the lead author on the study below, published a week later, this time in JAMA (March 6th issue) is Dr. Christopher D. Gardner of Stanford University:

Comparison of the Atkins, Zone, Ornish, and LEARN Diets for Change in Weight and Related Risk Factors Among Overweight Premenopausal Women
________
So here we have it. A straight-up comparison of 4 of the most popular diets, representing a spectrum of carbohydrate intake.

The study lasted for a year and was conducted as sanely and scientifically as any good study would be - using hundreds of women, hours of classroom instruction, books, handouts, incentive emails and phone calls, regular blood collections, regular dietary intakes ... incentive payments! Participants had an average education level beyond 4 years of college. Apart from locking these women up and rationing their food, this protocol, using this group of well-educated, motivated, financially- and socially-supported women, should have spelled dietary success.

Here are these women's weight losses:


The average weight loss across diets was 6 lbs, in one year. That's 1/2 pound per month.¹ The women selected for this study were required to be overweight or obese at baseline. So, it's not 6 lbs from an already slender frame.

Note that after 6 months, all groups started to regain weight lost. It would be interesting to see what their weights were a year after the study, after all those incentives ended.

The Winner?

It looks like Atkins edged out the other 3 diets when it came to weight loss. Atkins' women lost an average of 10 lbs in 12 months, compared to a combined average of 5 lbs for the other 3 groups. I would call that only winning by a nose, especially after a year of dieting. But a nose is a nose. And had women in the Atkins group actually been eating the Atkins diet, that nose might have been a full head length.

What Were Participants Actually Eating?

I created these charts from data in the study, a chart for each macronutrient: carbohydrate, protein, and fat. Diets often differ by macronutrient content. Gardner, et al., selected these diets based on their range of carbohydrates, from Atkins (low) to Ornish (high).²

Before you run out to purchase Dr. Atkins New Diet Revolution and start restricting your carbohydrates to less than 10% of calories, take a look at what these women were actually eating at 12 months (even with all that diet instruction and prodding) compared to what they were instructed to eat (their goal) in each diet category. It may be, as Gardner concluded, that for those who "initiate a low-carbohydrate diet ... weight loss is likely to be at least as large for any dietary pattern."




Two comments ... Atkins is not so much a high-protein diet as it is a high-fat diet. With all that fat, participants still lost weight and their lipids were better (more about that in a follow-up post.)

Also, notice how all the diets' carbohydrate, protein, and fat contents converged or sought a middle ground over time. If the diet's prescription was too extreme (e.g. very low fat: Ornish, or very low carb: Atkins), participants soon adjusted that to a middle ground. It's as if we naturally crave a certain proportion of carbohydrate, protein, and fat. Or at least that's what's easy, available, and tastes good.

One last thing, regardless of macronutrient content, all of the women had reduced their calorie intake by about 300 calories/day (at 12 months).

...Continued in "Fear Not The Fat".

________ ¹ About.com offers one critique of why the women in this study didn't lose more weight:
In Year-Long Study, Atkins Edges Out Competition
In a nutshell ... people who are insulin resistant (prediabetic) do better on a low carbohydrate diet, while people who are insulin sensitive do better on a low-fat diet. The study's random assignments resulted in mismatches.

However, this is exactly what randomization is designed to overcome, and does if a study has a large enough population. You can always cherry-pick the most sensitive individuals to receive an intervention, and show the intervention good. But how does the intervention fare in the real, non-cherry-picked world? The answer to that question lies in this study's findings.

² The LEARN diet (Lifestyle, Exercise, Attitudes, Relationships, and Nutrition) is based on the USDA's Food Guide Pyramid.

Cartoon via FunnyandJokes.com.

Sample Diet - Pop Quiz

Below is the food intake for a day in the life of the fictional Mrs. Baked Bean. Mrs. Bean is 43 years old. She stands 5' 5", weighs 145 lbs, works in an office, and smokes about a pack of cigarettes/day.

1. Can you name, just by looking at what she eats, one nutrient Mrs. Bean is getting plenty of, and one nutrient she definitely needs more of? (Examples of nutrients: vitamins, minerals, carbohydrate, fat, protein, calories, etc.)

2. Can you tell if Mrs. Bean is likely to gain weight, lose weight, or stay about the same weight eating like this? (The diet below provides about 2000 calories.)
________
Breakfast
Quaker Instant Oatmeal, apples and cinnamon, 1 pkg.
Starbucks Tall Latte w/nonfat milk, 12 oz.

Morning Snack
Banana, medium
Stonyfield Farm Lowfat Yogurt, strawberry, 6 oz.

Lunch
Pizza Hut Thin 'N Crispy Cheese Pizza, 2 slices from a medium pie
Diet Coke, 12 oz.

Afternoon Snack
Raisins, 1/4 cup
Quaker Chewy Chocolate Chip Granola Bar, 1

Dinner
Stouffer's Lean Cuisine Cafe Classics Baked Chicken and Whipped Potatoes and Stuffing Entree, 1
Broccoli, frozen, chopped, boiled, 1/2 cup
Butter, 1 tsp. for broccoli
Dinner Roll, 1 small
Butter, 1 tsp. for roll
Red Wine, 6 oz.

Evening Snack
Girl Scout Cookies, Samoas, 3
Silk Soymilk, Vanilla, 8 oz.
________
Update: March 7 - The following recommendations are based on Mrs. Bean's age and gender.

Doing Well:
Calcium recommendation: 1000mg
Calcium intake: ~1690mg

Total fat recommendation: 20 to 35% of calories
Total fat intake: ~25% of calories

To use hj's term, Needs Tweaking:
Vitamin C recommendation: 75mg + 35mg (smoker) = 110mg
Vitamin C intake: ~62 mg

Potassium recommendation: 4700mg
Potassium intake: ~2300mg*

* Alcohol intake increases risk for hypertension. (I suspect Mrs. Bean's admission of 6 oz. of red wine at dinner suffers from underreporting.) Potassium aids in blood pressure regulation.

Vitamin D recommendation: 200 IU (In light of recent research on bone health, heart health, and cancer, some are recommending 400 to 1000 IU and higher.)
Vitamin D intake: ~126 IU**

** Smoking increases risk for lung cancer. Vitamin D has been shown to improve lung cancer survival rates. Vitamin D is also produced in skin exposed to sunlight and Mrs. Bean gets precious little of that sitting in an office.

Since a few of you mentioned her iron intake, I'll post it. However, knowing Mrs. Bean, her love of red meat won't make iron or zinc a problem. (Richard: Good point regarding iron, which is best absorbed in an acidic environment. Ascorbic acid (vitamin C) aids in conversion of ferric iron (Fe3+) to ferrous iron (Fe2+) which is better absorbed. Although, hydrochloric acid (HCL), which is present in the stomach also performs this function.)

Iron recommendation: 18mg
Iron intake: ~13mg
________
Regarding her weight: (Lavender and hj are spot on.) Her current intake of ~2000 calories/day just about equals her expenditure of ~2000 calories/day. I predict her weight won't change that much in the next few weeks or months.

However, as Autumn pointed out, her weight is already a little high. Her BMI (body mass index) of 24.1 is on the high end of normal. Also, her expenditure (which is based on her age, height, current weight, and activity level) will decrease as she ages. If she changes nothing, she is looking at weight gain in the next 5 years. It would be a good idea for Mrs. Bean to slowing start shaving off 100 to 200 calories/day, or take up walking. Isn't life grand.
________

Garlic Fails to Live up to its Cholesterol-lowering Claim

This isn't going to bode well for garlic fiends. It might bode well for people who find themselves in the vicinity of garlic fiends, assuming garlic fiends give up their garlic habits. Though, if they're thinking about it, let it not be because of this one study.

Researchers from Stanford reported in the February 26th issue of the Archives of Internal Medicine, a sister publication to JAMA, that neither raw garlic nor garlic supplements improved cholesterol levels (LDL, HDL, triglycerides, total cholesterol) in participants during a 6-month trial.

Here's the abstract:
Effect of Raw Garlic vs Commercial Garlic Supplements on Plasma Lipid Concentrations in Adults With Moderate Hypercholesterolemia

WebMD has a nice synopsis:
Garlic May Not Lower Cholesterol: Study Shows No Improvement in Cholesterol Levels From Raw Garlic or Garlic Supplements

The authors investigated three garlic formulations, a dried garlic product (Garlicin), an aged garlic extract (Kyolic), and raw garlic. The study used wonderful research protocol, which won't forecast continued healthy sales for those supplements. But I have reservations about that raw garlic arm of the study.

Follow the Bouncing Clove

The raw garlic was provided as part of a condiment, to be added to a sandwich, which was also provided. Sandwiches were consumed daily, and along with their garlic condiments, were picked up twice a week. "Participants were instructed to heat the sandwich bread or filling as desired, but not the condiment because it contained the raw garlic and heat causes allicin loss." Allicin is the supposed active ingredient in garlic.

The garlic that was provided in the condiment that was provided in the sandwich that was provided to participants twice a week, and which, hopefully (because we can't follow these sandwiches after we release them to sandwich eaters) was always kept at a temperature no higher than 39.2ºF, did not come from a freshly squashed garlic clove. It came from an individually packaged 4 gram amount of previously crushed garlic that had been kept frozen at -80ºC (-112ºF) for some period of time. The authors don't say what that period of time was, but the following sentence provides a clue, "Allyl thiosulfinate content in raw garlic stored at -80ºC ... was unchanged after 2 years." While it may be fair to claim that the garlic consumed in the study was raw, it's a stretch to call it fresh.

Here are my reservations:

1. Allicin, a component of crushed garlic which was measured to be present in "stable amounts" throughout the trial, may not be the only active ingredient in garlic:
   
   "Garlic is important as a whole food or herb because [it supplies] many sulfur-containing and other phytochemicals which can have antioxidant and bioactivity."
   - Recent Advances on the Nutritional Effects Associated with the Use of Garlic as a Supplement
   
   
2. What other possibly active ingredients may have been depleted in the course of garlic being crushed, measured, packaged, super-frozen, held for some period of time (up to 2 years), thawed from -112ºF (without heat?), unpackaged and mixed into a condiment, packaged again, distributed to study participants, held for some period of time (up to 4 days), at temperatures sometimes above 39.2ºF, and possibly warmed (microwaved?) before consumption?
   
   
3. Garlic may provide cardiovascular (and other) benefit by means other than cholesterol lowering, e.g. through anti-clotting action, decreased atherosclerosis, or what the lead author himself describes:
   
   "It's still possible that garlic has an anti-inflammatory effect, or a blood-pressure-lowering effect, or an anticancer effect - all of which should be studied rigorously."
   - Christopher Gardner PhD, Stanford University

As with all studies, these results are only applicable to a population with similar characteristics as the study group - in this case a group that is primarily non-Hispanic white, post baccalaureate degree educated, and residents of one of the wealthiest areas in the country.

I'm sorry FRE, I'm sticking to my clove-a-day habit :)

________Photo: Homegrown.