I?m a 52-year-old menopausal woman. If I eat flax oil will this help the hot flashes I?m experiencing?
You need to be careful here. Flax oil contains alpha-linolenic acid, which can increase amounts of the eicosapentaenoic acid and docosapentaenoic acid (found in fish oils).8 Both these seem to have some positive health effects, for instance in heart disease.9 However, there are other phytonutrients such as flax lignans that are not generally extracted into the oil that may help with hot flashes. To get these phytonutrients it is best to consume the ground flaxseeds themselves—so don?t be fooled into thinking that all flax oil is as effective as ground flax. Flax lignans have a structure similar to estrogens that enable them to bind to estrogen hormone receptors in the body and prevent the estrogens themselves from binding. The lignans have a much more moderate effect on the receptor activity, possibly evening out the peaks and troughs in estrogen activity that seem to happen around menopause. Flax fiber may also bind to estrogens in the gastrointestinal tract, causing them to be flushed out rather than enter the body.
A recent study showed that post-menopausal women consuming their habitual diets plus 5 or 10 g of ground flaxseed showed lowered blood levels of estradiol and estrone compared to a group that ate no flaxseeds.10 Although this sounds good, the effects on hot flashes have not been that encouraging. One small study did not show any effect on hot-flash rate when supplementing with flaxseed.11 Another study looked at menopausal symptoms in general and showed no difference with flax seed use.12 On the positive side, a third study did show some mild improvement in overall menopausal symptoms,13 and I have also heard a number of anecdotal reports that flaxseed may help with these symptoms.
Given the fact that flaxseed does contain lignans and fiber that may have other positive benefits, it seems like it would be worth a try.
I have a family history of colon cancer. Should I be concerned about eating red meat?
A family history of colon cancer does increase your risk, and eating a lot of meat will increase your risk even more. The meat correlation is one that has rock-hard science behind it, according to a major study released this year. Based upon statistical calculations after following almost 500,000 men and women from 10 European countries for five years, researchers projected that the absolute risk for colorectal cancer development in a 50-year-old over the course of 10 years was 171 percent for the highest category of red and processed meat intake and 1.28 percent for the lowest category of intake.
Interestingly, they also found an inverse relationship with fish. In other words, the more fish a person consumed, the lower the colon cancer risk.7 Clearly, high consumption of red or processed meat significantly increases the risk for this disease. The results confirm what many doctors and nutritionists have believed for some time but until now did not have strong evidence to back it.
I?m often jet-lagged from cross-country trips. I?ve heard melatonin can help but am not sure when or how much to take. What do you recommend?
Melatonin, a hormone secreted by the pineal gland, is produced at night when levels rise to help our bodies regulate sleep-wake cycles. Scientists have long known that melatonin is involved in adjusting the body clock. When we change time zones, and therefore the time we normally sleep and awaken, we tend to throw off our body rhythms in terms of when and how much melatonin to produce.
Supplemental melatonin thus seems like a natural jet-lag antidote to resynchronize our hormonal rhythms. Yet, while there is a lot of hype about melatonin, the research on its use in jet lag is not crystal clear. Some studies are positive1,2 and some negative.3,4 Figuring out the right dose and correct time to take it is additionally confusing. In one double-blind, placebo-controlled study, volunteers received one of: 0.5-mg fast-release melatonin, 5 mg fast-release melatonin, 2 mg controlled-release melatonin or placebo. The medication was taken once daily at bedtime during four days after an eastward flight.5 Results showed that the 0.5 mg dose was almost as effective as the 5 mg dose and both the fast-release melatonin formulations were more effective than the slow-release formulation. All the melatonin doses were more effective than placebo, improving sleep quality and reducing fatigue and daytime sleepiness.
Another study showed that taking a 5 mg dose for five evenings—starting the night of arrival?worked better than starting the melatonin three days before leaving on the trip.6 So 5 mg on arrival for four to five days seems like a reasonable route to take.Dan Lukaczer, N.D., is director of clinical research at the Functional Medicine Research Center, a division of Metagenics Inc., in Gig Harbor, Wash.
1. Beaumont, M, et al. Caffeine or melatonin effects on sleep and sleepiness after rapid eastward transmeridian travel. J Appl Physiol 2004;96(1):50-8.
2. Pierard, C, et al., Resynchronization of hormonal rhythms after an eastbound flight in humans: effects of slow-release caffeine and melatonin. Eur J Appl Physiol 2001;85(1-2):144-50.
3. Edwards, BJ, et al. Use of melatonin in recovery from jet lag following an eastward flight across 10 time zones. Ergonomics 2000;43(10):1501-13.
4. Spitzer, RL, et al. Jet lag: clinical features, validation of a new syndrome-specific scale, and lack of response to melatonin in a randomized, double-blind trial. Am J Psychiatry 1999;156(9):1392-6.
5. Suhner, A, et al. Comparative study to determine the optimal melatonin dosage form for the alleviation of jet lag. Chronobiol Int, 1998;15(6):655-66.
6. Petrie, K, et al. A double-blind trial of melatonin as a treatment for jet lag in international cabin crew. Biol Psychiatry 1993;33(7):526-30.
7. Norat, T, et al. Meat, fish, and colorectal cancer risk: the European Prospective Investigation into cancer and nutrition. J Natl Cancer Inst 2005;97(12):906-16.
8. Tarpila, S, et al. The effect of flaxseed supplementation in processed foods on serum fatty acids and enterolactone. Eur J Clin Nutr 2002 56(2):157-65.
9. Rallidis, LS, et al. Dietary alpha-linolenic acid decreases C-reactive protein, serum amyloid A and interleukin-6 in dyslipidaemic patients. Atherosclerosis 2003, 167(2):237-42.
10. Hutchins, AM, et al. Flaxseed consumption influences endogenous hormone concentrations in postmenopausal women. Nutr Cancer 2001;39(1):58-65.
11. Dalais, FS, et al. Effects of dietary phytoestrogens in postmenopausal women. Climacteric, 1998;1(2):124-9.
12. Dodin, S, et al. The effects of flaxseed dietary supplement on lipid profile, bone mineral density, and symptoms in menopausal women: a randomized, double-blind, wheat germ placebo-controlled clinical trial. J Clin Endocrinol Metab 2005;90(3):1390-7.
13. Lemay, A, et al. Flaxseed dietary supplement versus hormone replacement therapy in hypercholesterolemic menopausal women. Obstet Gynecol 2002;100(3):495-504.
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