Pesticides related to ADHD
Prenatal vitamins reduce autism risk
Exercise preserves brain function
Cruciferous veggies lower mortality
Diet, lifestyle, and weight gain
Pesticides are toxic to humans as well as pests, especially when they accumulate in tissues from repeated exposure. They are even more harmful to children, who have fewer defenses and are more susceptible to their damaging effects, particularly to their undeveloped nervous systems.
A new study of trichlorophenols (TCP), which have been used in fungicides, herbicides, and pesticides, suggests that they are toxic to the nervous system with specific effects in children. Researchers in Florida examined urinary excretion of TCPs and any association with parent-reported attention deficit/hyperactivity disorders (ADHD).
They used data from the National Health and Nutrition Examination Survey to evaluate the association in 2546 children aged 6-15 years. They looked at three groups: those with “low” levels of TCPs in the urine (less than 3.58 mcg/g), those with “high” levels (more than 3.58 mcg/g), and those with undetectable levels (which, in practical terms, turns out to be the only truly low level when considering the health effects).
Compared to those children with levels below the limit of detection, those with low or high levels both had increased risk of parent-reported ADHD. The low level group had a 54 percent higher risk, and those with high levels had a 2.4-fold higher risk. It is clear from this report that no level of these toxic substances is safe for children. (Xu X, Urinary trichlorophenol levels and increased risk of attention deficit hyperactivity disorder among US school-aged children. Occup Environ Med. 2011 May 3. [Epub ahead of print]
This makes it all the more important, especially for parents, to choose organic foods when possible, and to choose wisely when it is not. The Environmental Working Group (www.ewg.org) just released an update of their list of the most and least contaminated foods (the Dirty Dozen and the Clean Fifteen). Apples now top the list of most-contaminated foods, followed by celery, strawberries, peaches and spinach. Among the least likely to be contaminated are onions, corn, pineapples, avocados, asparagus, and peas (you can see their complete list at their website). (The problem with corn, is that it is mostly genetically modified, so organic is a better choice.)
Autism has been on the rise in recent decades, and the reason is not clear. While there may be some genetic component to this, it is unlikely to be the main determinant of the condition, as genetics have not changed much over this time period. Symptoms include difficulties with communication and social skills, such as a delay in learning to talk (although some children may have learned to talk and then regressed to non-communicative states). They may also engage in repetitive behaviors (such as rocking and hand flapping), be resistant to affection, and have slow development in other areas.
A new study suggests that nutrition can make a difference in the risk of children becoming autistic. Researchers evaluated 288 children from two to five years old, who were confirmed to have autism, 141 with autism spectrum disorders, and 278 with normal development. They then retrospectively collected data on the mothers’ intake of vitamins before and during pregnancy.
Among those mothers who took prenatal vitamins for three months before pregnancy and during the first month of pregnancy, their children had a 38 percent lower risk of developing autism. For mothers with certain genetic variants of vitamin metabolism, the risks were up to 4.5 to 7.2 times higher if they did not take prenatal vitamins. (Schmidt RJ, et al., Prenatal vitamins, one-carbon metabolism gene variants, and risk for autism. Epidemiology. 2011 Jul;22(4):476-485.)
Many parents report that nutrition and environment play a role in autism, whether it is apparently caused in part by food allergies, sensitivity to food additives, environmental chemicals and toxic metals, or relieved by relatively high doses of vitamins, minerals, and essential fatty acids taken as supplements. Many diets have been proposed as treatments, and it is clear from experience that they help some children but not all. More research is definitely warranted in this field.
Exercise is important to maintain cardiovascular fitness, and it makes one feel more energetic and alert, improves mood, and helps to control weight. New information shows that it also helps to preserve brain function. Silent brain infarcts (SBI), or silent strokes, are subclinical vascular obstructions that lead to the loss of a small amount of brain tissue. Vascular disease of the brain is also reflected in a reduction of white matter volume. Over time, SBIs lead to cognitive decline and even dementia.
In a prospective population cohort study, researchers evaluated 1238 stroke-free participants aged 61 to 79 years. In this group, 60 percent were women and 65 percent were Hispanic. Overall, 43 percent reported no physical activity. (Willey JZ, et al., Lower prevalence of silent brain infarcts in the physically active: The Northern Manhattan Study. Neurology. 2011 Jun 8. [Epub ahead of print])
In this population, 197 participants had SBI. Those who reported the most physical activity, such as jogging, swimming or bicycling, had almost half the risk of SBI as those who reported the least physical activity. SBIs are seen on magnetic resonance imaging (MRI) in otherwise healthy elderly people. In addition to dementia, earlier studies have shown an association of SBI with a decline in psychomotor speed, a measure of reaction time, signal processing, and attention. This has serious implications for drivers, machine operators, those whose work depends on complex mental activity, and others.
It comes as no surprise that fruits and vegetables really are good for you, and new information confirms that they may promote cardiovascular health and enhance overall longevity. Researchers did an analysis of two studies on a total of 134,796 adults in China, including the Shanghai Women’s Health Study and the Shanghai Men’s Health Study. The women were followed for an average of 10.2 years, and the men for an average of 4.6 years.
They found that overall, fruit and vegetable intake was inversely related to the risk of total mortality in both men and women. A dose-response relationship was found particularly for cruciferous vegetables (these include mustards, broccoli, cabbage, cauliflower, bok choy, arugula, Brussels sprouts, and others), which had the most influence on mortality. (Zhang X, et al., Cruciferous vegetable consumption is associated with a reduced risk of total and cardiovascular disease mortality. Am J Clin Nutr. 2011 May 18. [Epub ahead of print])
Dividing the group into fifths (quintiles) of cruciferous vegetable intake, with each increasing quintile mortality was lowered by 9 percent, 12 percent, 15 percent, and finally 22 percent in the top quintile compared to the lowest. For total vegetable intake, the risks were lowered in each increasing quintile, and the top group had a 16 percent drop in mortality.
Most of the improvement in mortality had to do with lowered deaths from cardiovascular disease. Cruciferous vegetables (all in the mustard family) are rich in vitamin C, minerals, phytochemicals, and fiber, all of which help lower mortality. Asian diets are typically high in these vegetables, which may account for the lower mortality compared to western populations.
As people age, it is not uncommon in developed countries for them to gain weight. This is the average case in places like the U.S., but it is not physiologically normal or healthy. Once you are a fully grown adult in your late teens or early twenties, assuming you are not ill, it is normal and healthy for your weight to stay about the same for the rest of your life. However, most people gain weight because of their thoughtless health habits, including poor nutrition and a lack of exercise.
In a new study, researchers followed 120,877 U.S. men and women, who were normal weight at the start of the study, for up to 20 years. Within each four-year period during the study, participants gained an average of 3.35 pounds (that is about 14 pounds over the course of the study). Some specific foods were associated with more weight gain than others. For example, potato chips were responsible for about half of the weight gain. Other forms of potato were also implicated, mainly French fries (potatoes naturally have virtually no fat, but potato chips and fried potatoes are mostly fat).
Other foods that were independently associated with a portion of the weight gain included sugar-sweetened beverages (1.00 pound), unprocessed red meats (0.95), and processed meats (0.93 pound). This is in contrast with some foods that were associated with weight loss, including, in order of increasing benefit, vegetables (-0.22 pound), whole grains (-0.37), fresh fruits (-0.49), nuts (-0.57), and yogurt (-0.82 pound). (Mozaffarian D, et al., Changes in diet and lifestyle and long-term weight gain in women and men. N Engl J Med. 2011 Jun 23;364(25):2392-404.)
The influence of other lifestyle choices is also interesting. For each four-year period, physical activity was associated with a weight loss of -1.76 pounds, alcohol use with an increase of 0.41 pounds, and sleep (more weight gain with less than six or more than eight hours per night). Also of note, watching television was associated with a 0.31 pound increase for each hour of watching per day.
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