Recent Longevity News for the seven days ending 4/7/10.  You should consult your doctor if you are taking any medications.

Omega-3: Healthy no matter what? - Science Daily, 4/6/10 - :"Rancid fish oil smells bad and tastes so awful that no-one would want to swallow it. But if the fish oil is in capsules, it is impossible to smell if it is rancid or not. That is why it is important for us to examine whether rancid fish oil is less beneficial to health, or, at worst, harmful to anyone who takes it ... One of the possible negative impacts of ingesting rancid fish oil to which Frøyland is referring is what is known as oxidative stress in the cell membrane, i.e. where oxidants break down the cell membrane ... fish oil from capsules caused oxidation of the cell membrane, even when antioxidants had been added and when the capsules still had over a year left before their expiration date. Juice containing omega-3, on the other hand, produced no oxidation ... The fish oil in Smartfish products comes from the company Marine Harvest Ingredients AS and is manufactured from the discards from salmon production -- within an hour of the salmon being slaughtered" - That's why I don't buy cheap band X brands when I buy supplements. - Ben

Endocrine disruptors: Babies absorb the most bisphenol A - Science Daily, 4/5/10 - "The study revealed that babies and infants absorb the most BPA. Babies fed using PC bottles are the worst affected, on average taking in 0.8 micrograms of BPA per kilogram of body weight via bottles. This amount is well below the statutory minimum. "But the latest studies on rats have shown that even low doses can have a harmful impact on the development of the animals,""

Vitamin D may save 40,000 Canadian lives per year - Nutra USA, 4/2/10 - "The results of this study strongly suggest that the personal and economic burden of disease in Canada could be significantly reduced if the mean serum 25(OH)D level was increased from its current level of 67 nmol/L to the optimal level of 105nmol/L" - [Abstract] - See vitamin D at Amazon.com.

Smoking is dumb: Young men who smoke have lower IQs, study finds - Science Daily, 4/2/10 - "The average IQ for a non-smoker was about 101, while the smokers' average was more than seven IQ points lower at about 94, the study determined. The IQs of young men who smoked more than a pack a day were lower still, at about 90. An IQ score in a healthy population of such young men, with no mental disorders, falls within the range of 84 to 116"

Blueberries may protect muscles from exercise damage - Nutra USA, 4/2/10 - "Although it is difficult to deduce the biological significance of the data presented here from in vitro studies, one may speculate that consumption of blueberry fruit polyphenolics and particularly malvidin glycosides may be beneficial in alleviating the damaging consequences of oxidative stress in muscle tissue" - [Abstract] - See blueberry extract at Amazon.com.

Elevated CRP Level Linked to Decline in Executive Function and Frontal Lobe Damage - Medscape, 4/1/10 - "They found that higher levels of hs-CRP were associated with worse performance on tests of executive function, even after adjustment for age, sex, education, and cardiovascular risk factors. "It's not like these people are really cognitively impaired," Dr. Wersching emphasized, "but it's just they do worse than people who have a lower CRP.""

Higher Vitamin D Levels Linked to Lower Risk for Female Pelvic Floor Disorders - Medscape, 4/1/10 - "In women at least 50 years old with vitamin D levels of 30 ng/mL or higher (OR, 0.55; 95% CI, 0.34 - 0.91), the likelihood of urinary incontinence was significantly reduced" - See vitamin D at Amazon.com.

The Perils of Plastic - Environmental Toxins - Time Magazine, 4/1/10 - "The levels observed are considered well below the federal safety threshold of 50 micrograms per kg of body weight per day. But that recommendation was made 22 years ago, and in the time since, scientists have learned more about the effects of even a bit of BPA. In 1998, Patricia Hunt, a geneticist at Washington State University, found that female mice dosed with BPA had serious reproductive problems, including defective eggs. More recently, she published a study showing that the offspring of mice exposed to BPA while pregnant can end up with corrupted eggs, a situation that leads to trouble for their offspring ... As a synthetic estrogen, BPA can mimic hormones, those powerful chemicals, like testosterone and adrenaline, that run the body. Tiny amounts of hormones produce immense biological and behavioral changes" -See Stainless Steel Water Bottles at Amazon.com.  Also I've been replacing plastic containers with jars at Specialty Bottle.  Click here for wide mouth short.  Click here for jars that fit the Yogourmet yogurt maker.  Also, Pyrex products at Amazon.com.  I see at least one with glass lids.  Also Go Green GlassLock.

Vitamin D shows promise against seasonal ‘flu: Study - Nutra USA, 4/1/10 - "daily supplements of vitamin D3 reduced the influence of seasonal ‘flu (influenza A) by over 40 per cent ... The benefits of vitamin D supplementation were even more noticeable in children who had low levels of vitamin D at the start of the study, with a 74 per cent reduction in the incidence of ‘flu observed" - [Abstract] - See vitamin D at Amazon.com.

EPA: Bisphenol A Is a 'Chemical Concern' - WebMD, 3/31/10 - "Some experts are concerned that exposure to BPA and its weak estrogen-like effects during critical periods of human development may be associated with a wide range of health problems, including behavioral effects, reproductive problems, cancer, heart disease, and diabetes" -See Stainless Steel Water Bottles at Amazon.com.

Small amounts of chocolate lower BP, cut strokes and MIs - theheart.org, 3/31/10 - "those who ate the most chocolate—around 7.5 g per day—had a 39% lower risk of MI and stroke than individuals who ate almost no chocolate (1.7 g per day) ... It's important to read the small print with this study. The amount consumed on average by even the highest consumers was about one square of chocolate a day or half a small chocolate Easter egg in a week, so the benefits were associated with a fairly small amount of chocolate ... Before you rush to add dark chocolate to your diet, be aware that 100 g of dark chocolate contains roughly 500 calories"

• Antioxidant Content of Cocoa Powders - hersheys.com - See the chart near the bottom, there's a huge difference in antioxidants between the different forms.

Avodart May Lower Prostate Cancer Risk - WebMD, 3/31/10 - "those who took the drug Avodart had a 23% lower risk of being diagnosed with prostate cancer over four years of treatment, compared to men who did not take the drug" - See Avodart (dutasteride) at OffshoreRx1.com.

Sharp Rise in HPV-Related Oropharyngeal Carcinoma -- A Legacy of the "Sexual Revolution"? - Medscape, 3/30/10 - "The incidence of oropharyngeal carcinoma related to human papillomavirus (HPV) has been increasing in recent years, and there is speculation that this is the result of the "sexual revolution" of the 1960s" - Tell me about it (click here).  I passed the 5 year mark in February.  Somehow I made it through that with just a scratch.  See: Cancerous Growths: Mouth Growths - "if the cancer has spread to lymph nodes, the 5-year survival rate is only 25%"

Abstracts from this week's Doctor's Guide Nutrition/Dietetics plus abstracts from my RSS feeds (Click here for the journals, the PubMed ones at the top):

Eicosapentaenoic acid reduces rectal polyp number and size in familial adenomatous polyposis - Gut. 2010 Mar 26 - "Treatment with EPA-FFA for 6 months was associated with a mean 22.4% (95% CI 5.1% to 39.6%) reduction in polyp number (p=0.012) and a 29.8% (3.6% to 56.1%) decrease in the sum of polyp diameters (p=0.027). Global polyp burden worsened over 6 months in the placebo group (-0.34) unlike the EPA-FFA group (+0.09, difference 0.42 (0.10-0.75), p=0.011) ... EPA-FFA has chemopreventative efficacy in FAP, to a degree similar to that previously observed with selective cyclo-oxygenase-2 inhibitors. EPA holds promise as a colorectal cancer chemoprevention agent with a favourable safety profile" - See Mega Twin EPA at Amazon.com and Jarrow Max DHA at Amazon.com.

A "Hot" Topic in Dyslipidemia Management--"How to Beat a Flush": Optimizing Niacin Tolerability to Promote Long-term Treatment Adherence and Coronary Disease Prevention - Mayo Clin Proc. 2010 Apr;85(4):365-79 - "Approximately 5% to 20% of patients discontinued treatment because of flushing. Flushing may be minimized by taking niacin with meals (or at bedtime with a low-fat snack), avoiding exacerbating factors (alcohol or hot beverages), and taking 325 mg of aspirin 30 minutes before niacin dosing. The current review advocates an initially slow niacin dose escalation from 0.5 to 1.0 g/d during 8 weeks and then from 1.0 to 2.0 g in a single titration step (if tolerated). Through effective counseling, treatment prophylaxis with aspirin, and careful dose escalation, adherence to niacin treatment can be improved significantly"

Blueberry fruit polyphenolics suppress oxidative stress-induced skeletal muscle cell damage in vitro - Mol Nutr Food Res. 2010 Mar;54(3):353-63 - "These in vitro data support the concept that blueberry fruits or derived foods rich in malvidin glycosides may be beneficial in alleviating muscle damage caused by oxidative stress" - See blueberry extract at Amazon.com.

Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren - Am J Clin Nutr. 2010 Mar 10 - "Influenza A occurred in 18 of 167 (10.8%) children in the vitamin D(3) group compared with 31 of 167 (18.6%) children in the placebo group [relative risk (RR), 0.58; 95% CI: 0.34, 0.99; P = 0.04]. The reduction in influenza A was more prominent in children who had not been taking other vitamin D supplements (RR: 0.36; 95% CI: 0.17, 0.79; P = 0.006) and who started nursery school after age 3 y (RR: 0.36; 95% CI: 0.17, 0.78; P = 0.005). In children with a previous diagnosis of asthma, asthma attacks as a secondary outcome occurred in 2 children receiving vitamin D(3) compared with 12 children receiving placebo (RR: 0.17; 95% CI: 0.04, 0.73; P = 0.006)" - See vitamin D at Amazon.com.

Widespread Vitamin D Deficiency in Urban Massachusetts Newborns and Their Mothers - Pediatrics. 2010 Mar 22 - "Overall, 58.0% of the infants and 35.8% of the mothers were vitamin D deficient" - See vitamin D at Amazon.com.

Neat Tech Stuff :

• Vista Shortcut Overlay Remover -  PC World - Freeware removes the annoying arrows from the desktop icons.
• IconWorkshop™ - Make your own icons for Vista, XP and MacOS using a professional Icon Editor

Supplement Focus (Liothyronine/Cytomel®/Triiodothyronine (T3)):

Where to purchase (check with your doctor first):

• T3 at International Anti-aging Systems

News & Research:

• Antipsychotics Significantly Decrease Free Thyroid Hormone Concentrations - Doctor's Guide, 9/4/08 - "In patients who receive antipsychotic medication, levels of free thyroxine and free triiodothyronine show significant decreases that may affect thyroid hormone functional activity in some tissues, such as the liver"
• Best Thyroid Treatment? - Dr. Weil, 8/29/08
• Looking For The Fountain Of Youth? Cut Your Calories, Research Suggests - Science Daily, 7/3/08 - "While scientists do not know how calorie restriction affects the aging process in rodents, one popular hypothesis is that it slows aging by decreasing a thyroid hormone, triiodothyronine (T3), which then slows metabolism and tissue aging" - All the studies I've read seem to support the opposite:
  • Longer-lived Rodents Have Lower Levels Of Thyroid Hormone - Science Daily, 10/12/06 - "T4 levels varied significantly between all of the groups, with the shorter-lived groups having higher levels of T4 than longer-lived groups ... However, because T3, levels did not differ significantly among all the groups, further research in this area using larger sample sizes (numbers of rodents in each group) is needed"
    
  • ACUTE EFFECTS OF TRIIODOTHYRONINE REPLACEMENT THERAPY IN PATIENTS WITH CHRONIC HEART FAILURE AND LOW-T3 SYNDROME: A RANDOMIZED, PLACEBO-CONTROLLED STUDY - J Clin Endocrinol Metab. 2008 Jan 2 - "Low-triiodothyronine (T3) syndrome is a predictor of poor outcome in patients with cardiac dysfunction ... dilated cardiomyopathy (DC) ... In DC patients, short-term synthetic L-T3 replacement therapy significantly improved neuroendocrine profile and ventricular performance"
  • Low triiodothyronine: a strong predictor of outcome in acute stroke patients - Eur J Clin Invest. 2007 Aug;37(8):651-7 - "The 1-year mortality was 27.34% for low T3 and 19.37% for normal T3 cases (P = 0.006). A smaller percentage of patients with low T3 values were independent at 1 year compared to those with normal T3 values [54.2% vs. 68.7%, chi(2) = 12.09, P < 0.001, odds ratio (OR) = 0.53"
  • Natural killer activity and thyroid hormone levels in young and elderly persons - Gerontology 2001 Sep-Oct;47(5):282-8 - "Decreased serum concentrations of total T(3) may contribute to low NK activity in the 'almost healthy' subgroup of the elderly"
  • Does low tri-iodothyronine independently predict mortality in elderly hospitalised patients? -  Int J Clin Pract 2001 Jul-Aug;55(6):409-10 - "Our study shows an association of low serum T3 with patient mortality in elderly hospitalised patients"
• T3 Supplementation Raises Patients' Response to Sertraline - Clinical Psychiatry News, 11/06 - "The sertraline-T3 cohort also was much more likely (odds ratio 2.69) to go into remission by the sixth week of treatment. At that point, 58.5% (31/53) of the T3-augmented patients but only 38% (19/50) of the placebo group was in remission"
• Longer-lived Rodents Have Lower Levels Of Thyroid Hormone - Science Daily, 10/12/06 - "T4 levels varied significantly between all of the groups, with the shorter-lived groups having higher levels of T4 than longer-lived groups ... However, because T3, levels did not differ significantly among all the groups, further research in this area using larger sample sizes (numbers of rodents in each group) is needed"
• Thyroid Supplementation Enhances Antidepressant Response - Medscape, 9/21/06 - "Remission occurred in 31 patients (58.5%) receiving T3 compared with 19 patients (38%) in the placebo group" - See T3 at International Anti-aging Systems but check with your doctor first.
• T3 Therapy Not Yet Ready for Psychiatric Use - Clinical Psychiatry News, 2/05 - "Today, many patients with complaints of chronic malaise or fatigue approach their physician seeking T3 therapy, but the fact is that none of the handful of well-designed randomized controlled trials done since then has been able to confirm the initial report of superior outcomes ... There is reason for concern that supraphysiologic doses of T3 in this setting could interfere with protein and fat metabolism and interact synergistically with catecholamines to increase myocardial oxygen demand, with resultant increased arrhythmia, MI, heart failure, and death"
• Reply to Doctor Who States that T3 is Dangerous--Fibromyalgia, Hypothyroidism, Thyroid Hormone Resistance - DrLowe.com, 12/8/03
• Combinination Levothyroxine/Liothyronine Shows No Obvious Benefit Over Levothyroxine Alone in Patients With Primary Hypothyroidism - Doctor's Guide, 12/11/03
• Combination Therapy No Better Than T4 Alone for Primary Hypothyroidism - Medscape, 12/9/03
• Thyroxine Plus 3,5,3'-triiodothyronine Treatment for Depressed Patients with Hypothyroidism Does Not Improve Patient-Assessed Well-Being - Doctor's Guide, 10/30/03
• Thyroid Hormone T3 Doesn't Boost Effectiveness of SSRIs - Clinical Psychiatry News, 10/03
• Adding T3 to Paroxetine Adds No Benefit in Depressed Patients - Doctor's Guide, 4/28/03
• Algorithm-Based Treatment Shows High Lack Of Response To Selective Serotonin Reuptake Inhibitors - Doctor's Guide, 4/17/03 - "When the clinicians added T3, they found it was effective among 10 out of 16 women patients (62.5%), but was not effective in any of the 9 male patients who received it. Although values were within the normal range, patients who responded to T3 had higher serum thyroid-stimulating hormone levels than those who did not ... The effect of T3 may be related to thyroid function even within the normal range"
• Options for Treatment-Resistant Depression - Psychiatric Times, 7/02 - "Use of T3 may interfere with thyroid metabolism if taken chronically, so its use should generally be limited to two or three weeks. Doses of T3 between 25 mcg/day to 50 mcg/day are more effective than T4"
• Bipolar Patients Sensitive to Thyroid Function Variations - Doctor's Guide, 1/8/02 - "They studied 65 patients in the depressed phase of bipolar I disorder to test the hypothesis that patients with lower thyroid function, even within the normal range, might have a poorer response to treatment initially ... Outcomes were relatively poor unless patients had FTI [free thyroxine index] values above the median and TSH values below the median"
• Does thyroid supplementation accelerate tricyclic antidepressant response? A review and meta-analysis of the literature - Am J Psychiatry 2001 Oct;158(10):1617-22 - "This meta-analysis supports the efficacy of T(3) in accelerating clinical response to tricyclic antidepressants in patients with nonrefractory depression"
• Sustained Release T3 / Time Release T3 - WilsonSyndrome.com - "When Dr. Wilson first started treating Wilson's Thyroid Syndrome, Cytomel (instant release) was all he used. When he had about 300 patients at a time on Cytomel, he would get about 6-8 beeper pages over the weekend from patients having complaints and 2-3 of those calls would be about some pretty worrisome side effects. When Dr. Wilson conceived of and started using T3 mixed with a sustained release agent (see WTS history) he would go 6 months without a page"
• Synthroid / Armour Thyroid - WilsonSyndrome.com - "Some patients and physicians hear about the need for T3 and think they can gain the benefits of T3 by using Armour instead of Synthroid because it contains T3. But Armour thyroid doesn't contain just T3. It contains a lot of T4 as well! T4 is the very hormone we're trying to reduce in WTS in order to deplete RT3 levels"
• Thyroid Hormones Accelerate Depressive Response to Drug Therapy - Doctor's Guide, 10/30/01 - "Five of the six studies found T3 to be significantly more effective than placebo in accelerating clinical response ... Investigators say they found that the average effect was highly significant"
• The acute effect of calcium carbonate on the intestinal absorption of levothyroxine - Thyroid 2001 Oct;11(10):967-71 - "When 1,000 microg of levothyroxine alone was given to subjects, the maximum average total T4 absorption was 837 microg (83.7% of the dose ingested) at 120 minutes. When levothyroxine was coadministered with 2.0 g of calcium (as calcium carbonate), the maximum average T4 absorption decreased to 579 microg (57.9% of the dose ingested) at 240 minutes"
• Use OF T3 Thyroid Hormone to Treat Depression - DrMirkin.com, 5/19/01 - "some people become depressed when they take just T4 and their depression can be cured when they take both thyroid hormones, T3 and T4"
• Replacing T4 With Triiodothyronine Improves Cognition And Mood In Hypothyroidism - Doctor's Guide, 7/5/00 - "Substituting T3 for a portion of T4 changed the concentrations of thyroid hormones and thyroid-stimulating hormone (TSH) as well as improving cognition and mood"
• T3---fibromyalgia, hypothyroidism, thyroid hormone resistance - drlowe.com
• Wilson's Thyroid Syndrome - "Conversion of T4 to T3 can also be impaired by glucocorticoids" - Maybe that is the mechanism by which cortisol causes depression, and if so, could T3 then cure the depression? - Ben
• Adding Natural Hormone Boosts Brain Function In Hypothyroidism - Doctor's Guide, 2/11/99 - "We found there wasn't much difference between the two treatments in terms of metabolic effects or effects on various peripheral organs," Prange said. "There were big differences, however, in the mental state of the patients. If these findings hold up, they will be very important."
• Depression Management - ContinuingEducation.com, exp. 12/31/02 - See table six, recommends 5 - 50 mcg T3, 100 mcg (.1 mg) T4
• Liothyronine Sodium - RxList.com - "Twenty-five mcg of liothyronine [T3] is equivalent to approximately 1 gram of desiccated thyroid or thyroglobulin and 0.1 mg of L-thyroxine [T4]" - I don't know if that is correct concerning 1 gram of desiccated thyroid.  That would mean that it would take 17 of the normal 60 mg desiccated thyroid capsules to equal 25 mcg T3 and 100 mcg T4 (1000/60 = 17).  I would think that that amount would be lethal.  Maybe it should have been grains instead of grams.  Any feedback would be appreciated. - Ben

Abstracts:

• The pharmacodynamic equivalence of levothyroxine and liothyronine. A randomized, double blind, cross-over study in thyroidectomized patients - Clin Endocrinol (Oxf). 2009 Sep 10 - "The therapeutic substitution of L-T3 for L-T4 was achieved at approximately 1:3 ratio"
• Increased reverse T3 is associated with shorter survival in independently-living elderly. The Alsanut study - Eur J Endocrinol. 2008 Nov 10 - "rT3 was the only thyroid hormone associated with shorter survival"
• Higher Serum Free Thyroxine Levels Are Associated with Coronary Artery Disease - Endocr J. 2008 May 23 - "The relative risk (RR) for CAD in highest tertile of FT(4 )showed increased risk compared with the lowest tertile (RR 1.98; 95% CI 0.98-3.99, p<0.001). Our study showed that FT(4 )levels were associated with the presence and the severity of CAD. Also, this study suggests that elevated serum FT(4 )levels even within normal range could be a risk factor for CAD" - That might be an argument for going with T4 on say even days and T3 on odd days.
• ACUTE EFFECTS OF TRIIODOTHYRONINE REPLACEMENT THERAPY IN PATIENTS WITH CHRONIC HEART FAILURE AND LOW-T3 SYNDROME: A RANDOMIZED, PLACEBO-CONTROLLED STUDY - J Clin Endocrinol Metab. 2008 Jan 2 - "Low-triiodothyronine (T3) syndrome is a predictor of poor outcome in patients with cardiac dysfunction ... dilated cardiomyopathy (DC) ... In DC patients, short-term synthetic L-T3 replacement therapy significantly improved neuroendocrine profile and ventricular performance"
• Low triiodothyronine: a strong predictor of outcome in acute stroke patients - Eur J Clin Invest. 2007 Aug;37(8):651-7 - "The 1-year mortality was 27.34% for low T3 and 19.37% for normal T3 cases (P = 0.006). A smaller percentage of patients with low T3 values were independent at 1 year compared to those with normal T3 values [54.2% vs. 68.7%, chi(2) = 12.09, P < 0.001, odds ratio (OR) = 0.53"
• Free triiodothyronine and thyroid stimulating hormone are directly associated with waist circumference, independently of insulin resistance, metabolic parameters and blood pressure in overweight and obese women - Clin Endocrinol (Oxf). 2007 Jun 4
• A Comparison of Lithium and T3 Augmentation Following Two Failed Medication Treatments for Depression: A STAR*D Report - Am J Psychiatry. 2006 Sep;163(9):1519-30 - "After a mean of 9.6 weeks (SD=5.2) of treatment, remission rates were 15.9% with lithium augmentation and 24.7% with T(3) augmentation"
• T3 augmentation of SSRI resistant depression - J Affect Disord. 2006 Apr;91(2-3):211-5 - "The women took a mean daily dose of 40.6 mug of T3 for a mean duration of 3.75 weeks, while the men were on a mean daily dose of 43.8 mug of T3 for 3.5 weeks. T3 augmentation was associated with a statistically significant drop (p<.003) in the mean HAMD at end of the three weeks compared to baseline scores"
• Critical appraisal: Combined T3 and T4 replacement therapy is not better than replacement with T4 alone - Rev Med Chil. 2005 Sep;133(9):1116-9
• Natural killer activity and thyroid hormone levels in young and elderly persons - Gerontology 2001 Sep-Oct;47(5):282-8 - "Decreased serum concentrations of total T(3) may contribute to low NK activity in the 'almost healthy' subgroup of the elderly"
• Effect of triiodothyronine on mitochondrial energy coupling in human skeletal muscle - J Clin Invest 2001 Sep;108(5):733-7 - "these data suggest that T(3) promotes increased thermogenesis in part by promoting mitochondrial energy uncoupling in skeletal muscle"
• Topical triiodothyronine stimulates epidermal proliferation, dermal thickening, and hair growth in mice and rats - Thyroid 2001 Aug;11(8):717-24 - "hair length that was 1,180% longer ... 85% more hairs per millimeter ... topically applied thyroid hormone has dramatic effects on both skin and hair growth. These observations offer a new strategy for developing thyroid hormone and its analogues for treating disorders of skin and hair growth"
• Does low tri-iodothyronine independently predict mortality in elderly hospitalised patients? -  Int J Clin Pract 2001 Jul-Aug;55(6):409-10 - "Our study shows an association of low serum T3 with patient mortality in elderly hospitalised patients"
• Thyroid Hormone Replacement Therapy - Horm Res 2001 Jan;56 Suppl S1:74-81 - "Desiccated thyroid contains both thyroxine (T(4)) and triiodothyronine (T(3)); serum T(3) frequently rises to supranormal values in the absorption phase, associated with palpitations. Liothyronine (T(3)) has the same drawback and requires twice-daily administration in view of its short half-life ... TSH values of </=0.1 mU/l carry a risk of development of atrial fibrillation and are associated with bone loss although not with a higher fracture rate. It is thus advisable not to allow TSH to fall below - arbitrarily - 0.2 mU/l ... recent animal experiments indicate that only the combination of T(4) and T(3) replacement, and not T(4) alone, ensures euthyroidism [normal thyroid status] in all tissues of thyroidectomized rats ... It could well be that a slow-release preparation containing both T(4) and T(3) might improve the quality of life, compared with T(4) replacement alone, in some hypothyroid patients"
• Effects of thyroxine as compared with thyroxine plus triiodothyronine in patients with hypothyroidism - N Engl J Med. 1999 Feb 11;340(6):469-70 - "among 15 visual-analogue scales used to indicate mood and physical status, the results for 10 were significantly better after treatment with thyroxine [t4] plus triiodothyronine [t3]"

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