|
From The December 2000 Issue of Nutrition Science News
Nutrition Q&A
Dan Lukaczer, N.D.
'Tis the Season to Gain Weight
Q: I've heard that most weight gain over the course of a year occurs during the holidays. Is that true?
A: A good portion, yes, but certainly not all. The real problem, however, is people's inability to take it off afterward. Approximately one in two American adults is currently classified as overweight (27 percent) or obese (21 percent). For most adults, a slow and steady weight gain occurs in their 30s and 40s — approximately one to two pounds per year. While there is certainly a lot of congecture, little is really known as to whether to the long-term weight gain results from small, steady increases in weight throughout the year or from increased weight gain during concentrated times.
DHEA Long-Term Safety Unknown
Q: What is considered a safe dose of DHEA?
A: Dehydroepiandrosterone (DHEA) is a popular so-called antiaging supplement. This interest is not misplaced, because research supports its application in a variety of conditions. Because DHEA levels appear to decline with age, many authorities suggest it should be supplemented to levels found in young adults. DHEA reaches peak production in males about 20 years old and declines significantly after age 35. By age 75 the levels are perhaps 15 percent of their peak levels.2 Animal and human trials correlate DHEA supplementation with preventing heart disease and cancer.3
Somewhat overlooked is DHEA's safety profile. After all, DHEA is a steroid hormone that is a precursor to testosterone and estrogen—powerful hormones in even tiny amounts. Safety studies to date suggest moderate dosages of DHEA, 5 to 50 mg/day, appear to be relatively safe over the short term. A recent placebo-controlled study at the National Institute of Health and Medical Research in France of 280 men and women older than 60 taking 50 mg/day showed no significant problems over the course of one year.4 However, in this trial DHEA did increase testosterone levels in women — but not men. No side effects were reported from this rise, but anecdotally I have seen some women report symptoms of facial hair growth and acne consistent with elevated testosterone levels.
Exercise caution when recommending this hormone because no long-term studies have been done. There are reports that prolonged exposure to DHEA in postmenopausal women, particularly those with abdominal obesity, may be associated with late promotion of breast cancer.5 At the very least, periodic monitoring of DHEA levels, testosterone and estrogen should be conducted to keep track of long-term effects.
Get the Lead Out
Q: What is the best way to test for lead toxicity?
A: Lead is a ubiquitous toxic element in the environment and has been linked to a variety of health conditions. Lead affects the nervous system in particular, and even low-level exposure has been associated with reduced intelligence scores, lowered school achievement scores and Attention Deficit Hyperactivity Disorder (ADHD).6,7 The acceptable level of lead exposure has been repeatedly lowered during the past 20 years as smaller concentrations appear to exert subtle changes in learning and health.
In cases of short-term acute exposure such as from industrial sources, blood and urine tests are the best way to test for lead toxicity. Otherwise, use a reputable lab that assesses hair lead levels. In 1979 the U.S. Environmental Protection Agency published an authoritative study concluding that hair analysis is a useful tool for assessing long-term exposure for toxic elements.8 Use a good lab that has a strong reputation because many factors can give spurious results. Reports come back in parts per million, so you can see there is little room for error.
Dan Lukaczer, N.D., is director of clinical research at the Functional Medicine Research Center, a division of Metagenics Inc., in Gig Harbor, Wash.
References
1. Yanovski J, et al. A prospective study of holiday weight gain. N Engl J Med 2000 Mar 23;342(12);861-7.
2. Hinson JP, Raven PW. DHEA deficiency syndrome: a new term for old age. J Endocrinol 1999;163:1-5.
3. Gaby A. Dehydroepiandrosterone: biological effects and clinical significance. Altern Med Rev 1996;1:60-9.
4. Baulieu E. et al. Dehydroepiandrosterone (DHEA), DHEA sulfate, and aging: contribution of the DHEA age study to a sociobiological issue. Proc Natl Acad Sci USA 2000 Apr 11;97:4279-84.
5. Stoll B. Dietary supplements of dehydroepiandrosterone in relation to breast cancer risk. Eur J Clin Endocrinol 1999;53:771-5.
6. Thatcher R, et al. Effects of low levels of cadmium and lead on cognitive functioning in children. Arch Environ Health 1982;37(3):159-66.
7. Tuthill R. Hair lead levels related to children's classroom attention-deficit behavior. Arch Environ Health 1996;51(3):214-20.
8.U.S. EPA-600/4-79-049. Aug 1979.
|
