One Nation Under Salt: New Study Finds National Overdose

Despite general wide-spread knowledge that consuming too much salt is unhealthy--and despite the plethora of low-salt alternatives on supermarket shelves--new research finds Americans still eat prodigious quantities of salt, enough to easily be a cause of the national epidemic of hyper-tension (abnormally high blood pressure.)

Researchers from the Harvard School of Public Health--including celebrity doc, Walter Willett--took a simple approach. The study looked at multiple studies detailing per-person 24 hour urinary excretion of sodium over a 46 year period in the U.S. Because 95% of daily dietary sodium intake is excreted in the urine, the researchers were able to reasonably estimate sodium intake  from the data. And what they found was an alarmingly large scale over-consumption of salt.

The Harvard group found that on average Americans have been consuming more than twice the amount of sodium recommended for maintaining health by the Institute of Medicine. The recommended daily intake of sodium is just over half a teaspoon at 1500 mg (for young adults) and 1300 mg (for adults ages 50-70.) According to the study, adults are actually eating closer to 3712 mg of sodium per day, which is the equivalent of about 1.5 teaspoons. Our blood pressure rises just thinking about it. 

Celery, Peppers Protect Memory

A plant compound called luteolin (loo-tee-oh-lin), prevalent in celery, carrots and peppers, inhibits the production of memory damaging inflammatory molecules in the brain, a new study finds. The researchers at the University of Illinois, who have spent nearly a decade researching the anti-inflammatory properties of plant compounds, were able to show that luteolin improves cognitive health by acting directly on specialized (microglial) cells to reduce their production of inflammatory molecules in the brain. Apparently, by eating the luteolin-rich diet, elderly mice in the Illinois study were able to regain the cognitive abilities of young mice. The reserch has not been duplicated in people, but in the meantime, it's yet another incentive to eat vegetables.

A Seed Bank Grows in Wine Country

The Seed Bank in Petaluma, CA sells 387 varieties of tomato seeds.In a grand old abandoned bank building that sits at a dusty intersection on the edge of Sonoma wine country in the tiny town of Petaluma, an heirloom seed store has sprouted. The Seed Bank--the only outpost of the Missouri-based Baker Creek Seed Company, currently the nation's premier heirlooom seed producer--is a goldmine for the growing army of gardeners and small farmers in Northern California and beyond fighting to preserve and cultivate plant diversity. The cavernous old Main Street bank filled with colorful heirloom seed packets is a perfect symbol of sustainablity.

A Violet Jasper purple tomato grown from Baker Creek Seeds.The shelves of the Seed Bank hold 33 types of cucumber, 47 eggplants, and don't even get us started on the hundreds of tomatoes."Sub-arctic" tomatoes are on offer, so are watermelons that grow up to 40 pounds and are fiber-free. All of the seeds have been developed through traditional methods by dedicated seed-savers who use intricate cultivation techniques. Genetically Modified seeds are not allowed. This is not the homogenous super-market produce spit out by the yield-crazed American agricultural machine, this is agriculture as art. Mary Robinson's German Bicolor Tomato, Blue Curled Scotch kale, Pandora Striped Rose eggplant are things of beauty to behold.

Word has spread fast about the store. Michael Pollen, writer-in-chief of the sustainable food movement, has already stopped by to give a talk. And the store's speaker series this Fall includes Paul Greenburg, author of Four Fish, the Future of the Last Wild Food, and Rowen Jacobsen, author of American Terroir: Savoring the Flavors of Our Woods, Waters and Fields. If you can't make it to Petaluma, there is a website, and by all means order a hardcopy of the Baker Creek Heirloom Seed Catalog. Just looking at photos of Crookneck-Early Golden Summer Squash, American Purple Top Rutabega or Chichiquelite Huckleberries will give you faith in the future of humankind.

Tuna Salad, Light on the Mercury

It's not perfect, but researchers say chunk-light is a better choice.If our oceans weren't contaminated with mercury, canned tuna would be such a healthy food. Now researchers at the University of Nevada, Las Vegas have done the legwork to provide some useful guidelines as to which canned tuna has the least amount of mercury.

After analyzing 155 cans of solid-white, chunk-white and chunk-light tuna from three of the most popular national brands, the team found that chunk light tuna offers the best choice. Its contaminant level averaged 0.28 ppm (parts per million) mercury versus 0.5 ppm in chunk-white tunas. The explantion for the difference is that different canned varieities (albacore, chunk-white, chunk-light, etc) are made from different members of the tuna family tree. As a rule, the larger the fish, the more mercury its flesh will contain due to a phenomemon called biomagnification in which the bigger the fish, the more fish it eats, and the more mercury it is exposed to. Canned chunk-light tuna is made from skipjack, a relatively small member of the tuna family whereas chunk-white tuna is made from albacore, which is a larger fish.

While eating chunk-light tuna is a bit better, it's not perfect. At the 0.5 ppm level of chunk-white tuna, a 55-pound child can safely eat only one serving of white tuna every two weeks according to the researchers. These calculatations suggest the same child could eat the chunk-light tuna about every 10 days. Perhaps the worst news is that 55% of all tuna examined was above the U.S. Environmental Protection Agency's (U.S. EPA) safety level for human consumption (0.5 ppm), and 5% of the tuna exceeded the action level (of 1 ppm) established by the U.S. Food and Drug Administration (U.S. FDA.) As the authors concluded in the study published in the journal Environmental Toxicology and Chemistry, clearly more research and stricter regulation of mercury in canned tuna is desperately needed.

Click here to see the study abstract.

Hot Peppers Burn Fat

A pepper extract could burn off the spare tire.This research breakthrough may one day be seen as the dieters' Holy Grail. Korean researchers Jeong In Joo and Jong Won Yun (we are not making this up) have been able to demonstrate that capsaicin (the active compound responsible for the hot sensation in chile peppers) boosted the activity of genes associated with turning up the body's furnace, thereby accelerating fat burning in lab mice. What's more, the activities of several genes that control the production of fat cells were racheted down by capsaicin, so while the rats were fed a high-fat diet, they did not gain as much fat as control rats fed the same diet without capsaicin.

Dr. Merrell's Tip: Don't try capsaicin pills if you have stomach ulcers or acid reflux. For everyone else, these pills should be taken with food.

There is little doubt left from a growing body (no pun intended) of research in rodents and humans that capsaicin inhibits the accumulation of fat, but this Korean paper, published in Proteome (a heavy-duty bio-geek journal from the American Chemical Society), is the first to identifiy mechanisms of action, which in this case turn out to be regulation of genes that control the body's fat storage mechnisms--aka the Holy Grail of weight loss research.

To wildly oversimplify the implications for obesity researchers (you would have to be a DNA expert to truly grasp this latest breakthrough) capsaicin makes fat easier to burn off. Over the past couple of years, researchers have learned a great deal about the metabolic differences between the two different types of human fat; brown fat (brown adipose tissue or BAT) and white fat (white adipose tissue or WAT.) Brown fat acts like the body's furnace, it has a lot of mitochondria, which are energy-generating cell structures that create body heat as a by-product of energy.

Brown fat has a job in the body, whereas white fat is sort of the lazy freeloader of body fats. Brown fat is the type of fat that keeps hybernating animals warm in the winter. Thin people tend to have more brown fat than white fat. White fat is the stuff that accumulates around the mid-section, it sends off a lot of inflammatory molecules, and it has almost no real function in the body other than acting as a sort of giant condo development for more fat cells. The researchers from Daegu University in Kyungsan, Korea tell us that capsaicin makes bad white fat cells act like good brown fat cells. The previously immobile white fat becomes a source of energy for the body, and begins to burn off at an accelerated rate.

It's all very good news for fat researchers (that is, people who research the biological mechanisms of fat.) And for the average Joe, it means there may be a natural fat burning pill with limited side-effects in the pipeline. Currently, capsaicin can be purchased in the form of cayenne pepper supplements. It's certainly worth a try, with the caveat that people with uclers or senstive digestive systems should avoid taking too many pepper supplements, as they can irritate the stomach lining.

To read about the research, see the June 3rd web edition of Science News. For a summary of the recent findings, see J. Proteome Res., 2010, 9 (6), p 2797