More work needed: Omege-3 fatty acids and antioxidants

In the past, I have argued that antioxidants aren't necessarily good for you, since some level of oxidation is required to support metabolism. As with many areas of public health research, there are contradictions. An example is the role of poly unsaturated fatty acids (PUFAs) in health. Many studies of human and animal populations have shown a health enhancing effect, but biochemists worry about the potential for these highly reactive molecules to oxidize and form free radicals. Perhaps they can be good in some cases, and bad in others?

Seeing the Forest for the Trees
The problem of scaling up from biochemical and molecular biology to whole organism physiology is seems to be a classic example of research at different levels yielding different results. For example, studies of the amount of food waste Americans throw away come to very different conclusions about food waste compared to studies that sum total food produced and imported and subtract food consumed in this country. Another example are national estimates of CO2 production by industry versus measurements of actual CO2 increases in the atmosphere. A third example is the classic mismatch between single-leaf gas exchange measurements and whole forest flux readings. The effort to reconcile differing conclusions from different levels of inquiry seems especially productive.

Evidence of scale-dependent mismatch in Omega-3 fatty acid research
One issue, of course, are the many different kinds of omega-3 fatty acids. One kind in particular, DHA (EPA, also) seems especially important for health benefits. But even this specific molecule is controversial:

"Docosahexaenoic acid (DHA) has a significant role in neural membrane phospholipid metabolism, immune responses and the aging process. The difference in antioxidant testing results between animal and human studies and between in vitro and in vivo effects is discussed in terms of different end-points of oxidation. This chapter concludes with seven important unsettled nutritional questions that need future research. With so many unanswered questions, the conclusion is drawn that it would be imprudent to make dietary recommendations to the public before the mechanisms of polyunsaturated lipid nutrition, in vivo activity of antioxidants, and in vivo lipid peroxidation are better understood." LIPID OXIDATION — SECOND EDITION. Edwin N. Frankel. 2005.

"Free radicals and reactive oxygen species produced in cells may attack PUFAs resulting in the formation of more free radicals, specifically hydroperoxides. The hydroperoxides, in turn, may damage DNA ultimately leading to cancer. These effects have indeed been observed in some in vitro experiments, but not in actual human beings. Many studies have shown that fish oils actually retard aging and suppress so- called free radical diseases such as atherosclerosis and cancer. Other studies have shown that a daily EPA + DHA intake in excess of 2.3 grams decreases the production of superoxide, a potent cancer promoter. At least one in vitro and one animal experiment have observed that EPA + DHA kill human breast cancer cells via the formation of hydroperoxides, but that this effect is strongly inhibited by vitamin E. Thus, at this point, it is not entirely clear whether EPA + DHA exert part of their beneficial effect through an increase or a decrease in the production of free radicals and reactive oxygen species. The researchers recommend more work in this area, but emphasize that the major benefits of fish oils probably are associated with their ability to inhibit the synthesis of arachidonic acid-derived, pro-inflammatory eicosanoids."
Larsson, SC, et al. Dietary long-chain n-3 fatty acids for the prevention of cancer: a review of potential mechanisms. American Journal of Clinical Nutrition, Vol. 79, June 2004, pp. 935-45

It seems that omega-3s may actually increase oxidative stress, but possibly only in the right areas: "In mammary tumours, it is observed that long-chain fatty acids not only increase apoptosis, but also increase lipid peroxidation, and the apoptotic effect can be reversed by antioxidants. The rationale for use of n-3 FA dietary supplements in counteracting BC progression needs to be tested... while at the same time, the effect on whole-body lipid peroxidation needs to be monitored. "

British Journal of Nutrition (2002), 87:193-198 Cambridge University Press Review article n-3 Fatty acids and lipid peroxidation in breast cancer inhibition Basil A. Stoll

There is some evidence that antioxidants can protect against unwanted damage from reactive PUFAs, but also some evidence that PUFAs are inherently dangerous: "DHA enhances the susceptibility of the liver and kidney to lipid peroxidation concomitant with higher levels of DHA in these tissues, as shown by the fatty acid composition. In addition, Vitamin E is unable to protect membranes of the liver and kidney rich in DHA from lipid peroxidation, even after ingestion of the highest level of Vitamin E. "

British Journal of Nutrition (1997), 78:655-669 Cambridge University Press

General Nutrition. Changes in susceptibility of tissues to lipid peroxidation after ingestion of various levels of docosahexaenoic acid and vitamin E. Kazuhiro Kubo, Morio Saito, Tadahiro Tadokoro and Akio Maekawa

In conclusion, "The arachidonic acid cascade is arguably the most elaborate signaling system neurobiologists have to deal with." Piomelli, Daniele (2000). "Arachidonic Acid". Neuropsychopharmacology: The Fifth Generation of Progress.

Biomes of the World

Chart is from Dr. Craine at WildPlants


from GAIM NPP modeling 1995-1997

Carbon Considerations

How much CO2 does flying emit compared with cars, and how much would it cost to offset that?

The average airplane flight emits about 0.4lb of CO2 per passenger mile. Compare that to a decent 20mpg car, which emits about 1lb of C02 per mile. Of course, if you carpool, you can divide that by the number of passengers. This confirms most calculations I have seen that show that flying gets about 70 mpg per passenger (source) However, because the effect of CO2 at that altitude is greater, a correction factor gives an effective mpg of 35mpg per passenger, still better than most cars, but not if you carpool. If your flight isn't completely booked, your share of the CO2 emitted would be even greater. In general, about 20lb CO2 are emitted per gallon of gas (source)

So, driving or flying 2,000 miles would emit 800 lb and 2,000 lb, respectively. But for two people, the figures for flying would become 1,600 lb, versus 2,000 lb driving. Let's just say that it's about a ton.

What would it take to offset these emissions?

To offset one ton carbon costs about $15. A number of companies will do this. "Afforestation of crop or pasture land is estimated to have the potential to sequester
between 2.2 and 9.5 metric tons of CO2 per acre per year. Reforestation is estimated at 1.1 to 7.7
metric tons of CO2 per acre per year." (source: Congressional Research Service) So a fraction of an acre could sequester the carbon from a cross-country airplane flight.


Interestingly, the cost to plant an acre of trees is $250-$2,000/acre (average: $500). According to this analysis, if afforestation (greatest potential to sequester carbon) cost $200/acre it could be profitable at a carbon price of $21/ton.

Growing Season

"The growing season has begun throughout the Northeast and the Growing Degree Days (GDD) are accumulating. This is a tool that farmers and gardeners use to track crop progress and to manage pest infestations. As the map above indicates, as of May 23, 2010, the GDD accumulation in most of the Northeast is 1 to 2 weeks ahead of normal. Reports from the National Agricultural Statistic Services show that the impacts of an advanced season are varied. Most states in the region reported that field crop and fruit progress is ahead of normal. While it's beneficial to get the field crops in early so the crop has time to mature, the early fruit bloom and emerging vegetables were damaged by the frost that occurred during the second week in May. The frost was considered a late frost in southern parts of the region, but well within the normal range for the northern states." from NRCC.

Adaptive Nitrogen Management

Harold M. van Es, Cornell University Department of Crop and Soil Sciences, Soil Health

Dr. van Es introduced his team's effort at a comprehensive, quick, and cheap soil test that goes beyond the standard chemical measurements to include physical and biological properties as well. I would like to see a paper showing how much variation in yield (b/c that is the output variable of interest to farmers) this test can account for, compared to other more comprehensive tests or even expert in-field evaluation.

Dr. van Es than discussed his work creating an adaptive nitrogen management tool that would completely bypass soil tests. His on-line tool uses rainfall patterns to estimate loss of nitrogen from corn fields and than recommends how much "booster" N to add. The benefits include less overall use of N. Interestingly, the loss of N in wet weather is exacerbated in soils with high organic carbon because of increased decomposition rates, according to Dr. van Es. Unfortunately, he did not discuss the dynamics of N under alternative farming (no synthetic fertilizer, no-till with cover crops, etc) practices that could obviate the need to even add N. I realized that one thing that's nice about monoculture corn across most of the mid-West is that the standardization makes it easier for science research to be relevant to a lot of people. It would be harder for Dr. van Es to research all the different alternative management techniques and apply recommendations for adaptive management to each.

The reason for internet-based adaptive management is a lack of real-time on-the-ground data on, say, soil moisture levels, N content, etc. But this is changing and Dr. van Es did show a few slides about what may be the future, with combines and irrigation equipment festooned with hi-tech spectrometers to gauge how much N plants have. The technique has been shown to be successful with wheat, but is still being developed on other crops.

Some links:

Sustainable Agriculture Research and Education

Alternative Farming Systems Information Center

Mercury in your Mouth

Mercury has a number of toxic effects and for that reason much work has gone into eliminating mercury from the environment. Although CFC lightbulbs do contain mercury, the government hopes people won't break them, and mercury thermometers have been generally discontinued. The coal industry has spent millions of dollars to combat the problem of mercury emissions, as have other chemical industries. Unfortunately, one place we've forgotten to look is in our own mouths.

Mercury or Amalgam fillings are shiny and metallic and have been used for a least 150 years to fill cavities in human teeth. Currently, their installation and use is not regulated under environmental laws, despite clear research showing that "dental amalgam is the greatest source of mercury vapour in non-industrial settings, exposing the concerned population to mercury levels significantly exceeding those set for food and for air." (WHO)

The problem is not trivial: in the U.S. dental amalgam accounts for about 11 percent of total mercury use, and emits between .6 tons/year and 10 tons/year (more than hazardous waste combusters, cement, etc). (EPA) These emissions are from cremations (~3 tons), water passing through humans (1-10 tons from 300 million americans, each excreting 3-100 micrograms per day) dentist offices (2-25 tons a year from 35-522mg/day/dentist). The totals are less than coal power plants (52 tons/year), but still significant. In Washtington state, King county has mandated the disposal of dental amalgam fillings in a hazardous waste disposal facility and states that "Amalgam particles removed from teeth should be collected, dried, placed in sealed containers, labeled and disposed of only to those qualified waste handlers and waste sites that do not incenerate or burn solid wastes. " Apparently the only place the stuff is safe is in our mouths.

The EPA Reference Dose for safe exposure to mercury is 0.1 micro g/kg/day and the FDA can remove food product from the shelf if it is found to contain more than 1 ppm mercury. Individuals with amalgam fillings ingest 3 to 100 micrograms of mercury per day, easily putting them over both limits. Depending on the number, size, and age of the fillings, the effective dose can be equivalent to eating several cans of tuna a day, each and every day. ( Environmental and Toxicological Concerns of Dental Amalgam and Mercury. Scarmoutzos, Louis and Boyd, Owen. )

In addition, dental amalgam in contact with dissimilar metals may generate galvanic corrosion which would release inorganic mercury (which is water soluble and readily transportable in the environment). Gastrointestinal microorganisms in humans can form methylmercury (the more dangerous form of mercry) from inorganic mercury. Studies have documented that dental amalgam is indeed bioavailable, at least to goldfishes. (Christopher J. Kennedy, “Uptake and accumulation of mercury from dental amalgam in the common goldfish, Carassius auratus,” Environmental Pollution 121, no. 3 (March 2003): 321-326.)

These environmental and personal health issues have convinced me to have my fillings removed and replaced with plastic composite. I would strongly urge anyone else with health concerns about their mercury fillings to also do the research, and then make their own decision. As with many areas of science, the evidence for harm is not complete, and much more research needs to be done. However, I believe that there is sufficient evidence to act.

Inequality and Wealth

The unlinking of Top 1% income from all those below them is simultaneous of another trend which is hard to measure, and often overlooked: increasingly, health and human hapiness have stopped tracking GDP and wealth. Correlation, or causation? Would greater equality lead to higher standard of living? Why? In the 1960's President Kennedy stated that a "rising tide would lift all boats," which was generally true, but something changed in the early 1980's.

http://www.huffingtonpost.com/2009/08/14/income-inequality-is-at-a_n_259516.html

The Environment and Natural Resources

read more...

A number of attempts have been made to conceptualize humanity's use of the planet: are we using too much? Calculations based on how much land is needed to produce the food, fuel, housing, transportation, and consumer products for the average American are used to show that it would take five planets to sustainably produce what Americans consume every year. These measurements, codified as the Ecological Footprint (seen above for the entire Earth), are based on the renewable productivity of standardized land uses such as agriculture, forest, and grassland.

Ecological Footprint versus Ecological Health
However, the size of the Ecological Footprint does not take into account most forms of pollution (heavy metals, estrogen mimics, etc) and in general does a poor job of accounting for the differing health of ecosystems. Indeed, according to the Ecological Footprint, non-renewable high-intensity resource use may "use" less land than renewable low-intensity resource use. The problem with this landscape landuse metric is that its focus on "biocapacity" can be at odds with biodiversity and ecosystem health, which the Ecological Footprint does not measure.

Much of this analysis is taken directly from Lenzen, M., C. Borgstrom Hansson and S. Bond (2007) On the bioproductivity and land disturbance metrics of the Ecological Footprint. Ecological Economics 61, 6-10.

Can biotechnology feed the world?

Some discussions recently have been inspired by the recent visit of Ms. Revathi, a schoolteacher-turned-organic farming advocate from India. Ms. Revathi visited the School of Environment and Natural Resources at OSU last week, bringing stories of widespread suffering from the Green Revolution and ongoing injustices from free trade, industrialization, capitalism, and corporations. She argues that ecologically- and traditionally-minded development can create healthy, prosperous farmers, while the American model has brought environmental, social, and economic ruination.

from Diaz, Robert J. and Rosenberg, Rutger. Spreading Dead Zones and Consequences for Marine Ecosystems. Science 15 August 2008: Vol. 321. no. 5891, pp. 926 - 929

Her viewpoint is uniquely different from that of main-stream American discourse about globalization, free markets, and the benefits of technology. Her years of experience growing sustainable farms in India seems similar to the experience of independent American local organic farmers, but leads her to make conclusions almost opposite to beliefs so accepted they are almost obvious to most Americans; for example, that the world has become better: wealthier, healthier, happier, etc because of technology, corporations, and development.

In some ways, the arguments of those who speak for the establishment, pass right through and do not apply to those who see the world differently. One of the best examples of this is a Congressional meeting held almost exactly 10 years ago. For the most part, these issues about biotechnology and aid, are still unresolved. This meeting was notable because it brought together some of the biggest hitters from both camps, who proceeded to talk right past each other, thoroughly confusing the moderater. Can there be a middle ground?

Life Support for the American Elm