Tryptophan, serotonin, and aging 色氨酸，血清素和衰老
Beginning with the industrial production of glutamic acid (sold as MSG, monosodium glutamate), the public has been systematically misinformed about the effects of amino acids in the diet. The FDA has been industry's powerful ally in misleading the public. Despite research that clearly showed that adults assimilate whole proteins more effectively than free amino acids, much of the public has been led to believe that “predigested” hydrolized protein and manufactured free amino acids are more easily assimilated than real proteins, and that they are not toxic. Even if free amino acids could be produced industrially without introducing toxins and allergens, they wouldn't be appropriate for nutritional use. 从谷氨酸(以味精、谷氨酸钠出售)的工业化生产开始，公众就被系统性地误导了，对饮食中氨基酸的影响。在误导公众方面，FDA一直是食品工业的有力盟友。尽管研究清楚地表明，成年人吸收全蛋白质比吸收游离氨基酸更有效，但许多公众一直被误导，认为“预先消化”的水解蛋白质和合成的游离氨基酸比真正的蛋白质更容易被吸收，而且它们是无毒的。即使游离氨基酸可以工业化生产而不引入毒素和过敏原，它们也不适合用于营养用途。
Although some research shows that babies up to the age of 18 months can assimilate free amino acids, a baby formula containing hydrolyzed protein was associated with decreased serum albumin, which suggests that it interfered with protein synthesis. 尽管一些研究表明18个月以下的婴儿可以吸收游离氨基酸，但含有水解蛋白的婴儿配方奶粉与血清白蛋白减少有关，这表明它干扰了蛋白质的合成。
The myth that free amino acids are “natural nutritional substances” has been used to promote the use of many products besides MSG, including aspartame, chelated minerals, and tryptophan. 游离氨基酸是“天然营养物质”的神话已经被用来推广味精以外的许多产品的使用，包括阿斯巴甜、螯合矿物质和色氨酸。
Although several amino acids can be acutely or chronically toxic, even lethal, when too much is eaten, tryptophan is the only amino acid that is also carcinogenic. (It can also produce a variety of toxic metabolites, and it is very susceptible to damage by radiation.) Since tryptophan is the precursor of serotonin, the amount of tryptophan in the diet can have important effects on the way the organism responds to stress, and the way it develops, adapts, and ages. 虽然有些氨基酸可能会急性或慢性中毒，甚至致命，但过量食用时，色氨酸是唯一一种致癌的氨基酸。(它还能产生各种有毒的代谢物，而且很容易受到辐射的损害。)由于色氨酸是血清素的前体，饮食中色氨酸的含量对机体应对压力、发育、适应和衰老的方式有重要影响。
When an inflammatory disease (eosinophilia-myalgia syndrome) was noticed in people using tryptophan tablets (1989-90), there was an intense campaign to exonerate the tryptophan itself by blaming the reaction on an impurity in one company's product. But the syndrome didn't occur only in the people who used that company's product, and similar changes can be produced by a high-tryptophan diet (Gross, et al., 1999). 当使用色氨酸片剂的人出现炎症(嗜酸性肌痛综合征)时(1989-90)，一场激烈的运动将色氨酸本身的反应归咎于某公司产品中的杂质，从而为其辩护。但该综合征并不只发生在使用该公司产品的人身上，高色氨酸饮食也会产生类似的变化(Gross等人，1999)。
There are people who advocate the use of tryptophan supplementation or other means to increase serotonin in the tissues as a treatment for the fibromyalgia syndrome, but the evidence increasingly suggests that excessive serotonin, interfering with muscle mitochondria, is a major factor in the development of that syndrome. 有人提倡使用色氨酸补充剂或其他方法来增加组织中的血清素，以治疗纤维肌痛综合征，但越来越多的证据表明，过量的血清素干扰肌肉线粒体，是该综合征发展的一个主要因素。
In 1965, Hans Selye showed that the injection of serotonin caused muscular dystrophy. Subsequent studies suggest that serotonin excess is involved in both muscular and nervous dystrophy or degeneration. (O'Steen, 1967; Narukami, et al., 1991; Hanna and Peat, 1989.) 1965年，Hans Selye证明注射血清素会导致肌肉萎缩。随后的研究表明，血清素过量与肌肉和神经营养不良或退化有关。(1967;鸣等人，1991;Hanna和Peat, 1989年)。
The fatigue produced by “over-training” is probably produced by a tryptophan and serotonin overload, resulting from catabolism of muscle proteins and stress-induced increases in serotonin. Muscle catabolism also releases a large amount of cysteine, and cysteine, methionine, and tryptophan suppress thyroid function (Carvalho, et al., 2000). Stress also liberates free fatty acids from storage, and these fatty acids increase the uptake of tryptophan into the brain, increasing the formation of serotonin. Since serotonin increases ACTH and cortisol secretion, the catabolic state tends to be self-perpetuating. This process is probably a factor influencing the rate of aging, and contributing to the physiological peculiarities of aging and depression. “过度训练”产生的疲劳很可能是由色氨酸和血清素超载产生的，这是由肌肉蛋白质的分解代谢和压力引起的血清素增加造成的。肌肉分解代谢也释放大量的半胱氨酸，而半胱氨酸、蛋氨酸和色氨酸抑制甲状腺功能(Carvalho, et al.， 2000)。压力也释放了储存的游离脂肪酸，这些脂肪酸增加了大脑对色氨酸的吸收，增加了血清素的形成。由于血清素增加ACTH和皮质醇的分泌，分解代谢状态趋向于自我延续。这一过程可能是影响衰老速度的一个因素，并有助于衰老和抑郁的生理特性。
Malnutrition, and specifically protein deficiency, produces an inflammatory state that involves extreme serotonin dominance. Stress or malnutrition prenatally or in infancy leads to extreme serotonin dominance in adulthood. Other functions of tryptophan are reduced, as more of it is turned into serotonin. 营养不良，特别是蛋白质缺乏，会产生一种炎症状态，这种状态涉及到极端的血清素支配。产前或婴儿时期的压力或营养不良会导致成年后血清素的极端支配。色氨酸的其他功能减弱，因为更多色氨酸被转化为血清素。
Decreasing tryptophan or decreasing serotonin improves learning and alertness, while increased serotonin impairs learning. 减少色氨酸或减少血清素可以提高学习能力和警觉性，而增加血清素则会损害学习能力。
Tryptophan is an essential amino acid for reproduction and growth of the young animal. Most research on the nutritional requirements for amino acids has been done on farm animals, because of the economic incentive to find the cheapest way to produce the fastest growth. Farmers aren't interested in the nutritional factors that would produce the longest-lived pigs. Some research has been done on the amino acid requirements of rats over a significant part of their short lifespans. In rats and farm animals, the amount of tryptophan required decreases with time as the rate of growth slows. 色氨酸是幼动物繁殖和生长所必需的氨基酸。大多数关于氨基酸营养需求的研究都是在农场动物身上进行的，因为经济诱因是寻找最便宜的方法以获得最快的增长。农民们对生产寿命最长的猪的营养因素不感兴趣。在老鼠短暂的寿命中，有相当一部分对氨基酸的需求进行了研究。在大鼠和农场动物中，色氨酸的需求量随着生长速度的减慢而随着时间的推移而减少。
In some ways, rats never really mature, since they keep growing for nearly their whole lifespan. Their growth stops just a short time before they die, which is usually around the age of two or three years. (At this age, rats' cells still retain approximately the same high water content seen in the cells of a two year-old child.) They usually become infertile about half-way through their lifespan. If we try to draw conclusions about amino acid requirements from the rat studies, I think we would want to extrapolate the curve for the decreasing need for tryptophan, far beyond the point seen during the rat's short life. And those “requirements” were determined according to the amounts that produced a maximum rate of growth, using the index of the pig farmers, as if the rats were being studied for possible use as meat. 在某些方面，老鼠永远不会真正成熟，因为它们在几乎整个生命周期中都在生长。它们的生长在死亡前很短的一段时间内停止，通常是在两三岁左右。(在这个年龄，老鼠的细胞仍然保持大约两岁儿童细胞的高含水量。)它们通常在寿命的一半左右变得不能生育。如果我们试图从老鼠的研究中得出氨基酸需求的结论，我想我们会推断出色氨酸需求减少的曲线，远远超出老鼠短暂生命中看到的点。而这些“需求”是根据产生最大生长率的数量来确定的，使用的是养猪户的指数，就好像是在研究老鼠是否可以用作肉一样。
When rats were fed a diet completely lacking tryptophan for a short period, or a diet containing only one fourth of the “normal” amount for a more prolonged period, the results were surprising: They kept the ability to reproduce up to the age of 36 months (versus 17 months for the rats on the usual diet), and both their average longevity and their maximum longevity increased significantly. They looked and acted like younger rats. (A methionine-poor diet also has dramatic longevity-increasing effects.) 当老鼠在短时间内完全缺乏色氨酸，或在更长时间内只含有“正常”量的四分之一的饮食时，结果令人惊讶:它们的繁殖能力一直保持到36个月大(而正常饮食的老鼠只有17个月大)，它们的平均寿命和最大寿命都显著增加。它们看起来和行为都像年轻的老鼠。(缺乏蛋氨酸的饮食也有显著的长寿效果。)
On the tryptophan-poor diet, the amount of serotonin in the brain decreased. When brain serotonin decreases, the level of testosterone in male animals increases. More than 20 years ago, a chemical (p-chlorophenylalanine) that inhibits serotonin synthesis was found to tremendously increase libido. 在缺乏色氨酸的饮食中，大脑中血清素的数量减少了。当大脑血清素减少时，雄性动物的睾丸激素水平就会增加。20多年前，人们发现一种化学物质(对氯苯丙氨酸)可以抑制血清素的合成，从而极大地提高性欲。
In old age, the amount of serotonin in the brain increases. This undoubtedly is closely related to the relative inability to turn off cortisol production that is characteristic of old age (Sapolsky and Donnelly, 1985). Hypothyroidism increases the formation of serotonin, as does cortisol (Henley, et al., 1997, 1998; Neckers and Sze, 1976). 随着年龄的增长，大脑中血清素的含量会增加。毫无疑问，这与老年特有的相对不能停止皮质醇的产生密切相关(Sapolsky和Donnelly, 1985)。甲状腺机能减退会增加血清素的形成，皮质醇也是如此(Henley等人，1997,1998;Neckers and Sze, 1976)。
In white hair, the amount of tryptophan is higher than in hair of any other color. Although serotonin and tryptophan are very important during rapid growth, their presence in senile tissues is probably closely associated with the processes of decline. The hair loss that occurs in hypothyroidism, postpartum syndrome, and with the use of drugs such as St. John's wort (which can also cause the “serotonin syndrome”) could be another effect of excess serotonin. 在白发中，色氨酸的含量高于任何其他颜色的头发。虽然血清素和色氨酸在快速生长过程中非常重要，但它们在老年性组织中的存在可能与衰老过程密切相关。甲状腺功能减退症、产后综合症以及服用圣约翰草(也能导致“血清素综合症”)等药物导致的脱发可能是血清素过量的另一个影响。
Serotonin stimulates cell division and tends to increase the formation of connective tissue, so its formation should be closely regulated once full growth is achieved. It contributes to the age- or stress-related thickening of blood vessels, and other fibrotic processes that impair organ function. 血清素（5-羟色胺）刺激细胞分裂，并倾向于增加结缔组织的形成，因此，一旦完全生长完成，它的形成应该受到密切的调控。它会导致与年龄或压力相关的血管增厚，以及其他损害器官功能的纤维化过程。
The metabolic rate (eating more without gaining extra weight) and ability to regulate body temperature are increased by early tryptophan deprivation. (Ashley and Curzon, 1981; Segall and Timiras, 1975.) The ability to oxidize sugar is impaired by serotonin, and several drugs with antiserotonin actions are being used to treat diabetes and its complications, such as hypertension, obesity, and foot ulcers. 早期色氨酸剥夺会提高代谢率(吃得更多而不增重)和调节体温的能力。(Ashley and Curzon, 1981年;西格尔和蒂米拉斯，1975年。)血清素削弱了人氧化糖的能力，几种具有抗血清素作用的药物被用于治疗糖尿病及其并发症，如高血压、肥胖和足溃疡。
An excess of tryptophan early in life, stress, or malnutrition, activates the system for converting tryptophan into serotonin, and that tendency persists into adulthood, modifying pituitary function, and increasing the incidence of pituitary and other cancers. 在生命早期，如果色氨酸过量、压力或营养不良，就会激活色氨酸转化为血清素的系统，这种趋势会持续到成年，改变脑垂体功能，增加脑垂体和其他癌症的发病率。
Serotonin's contribution to high blood pressure is well established. It activates the adrenal cortex both directly and through activation of the pituitary. It stimulates the production of both cortisol and aldosterone. It also activates aldosterone secretion by way of the renin-angiotensin system. Angiotensin is an important promoter of inflammation, and contributes to the degeneration of blood vessels with aging and stress. It can also promote estrogen production. 血清素对高血压的影响已被证实。它可以直接激活肾上腺皮质，也可以通过激活脑垂体来激活。它刺激皮质醇和醛固酮的产生。它还通过肾素-血管紧张素系统激活醛固酮的分泌。血管紧张素是炎症的重要促进剂，随着年龄的增长和压力的增加，血管发生退行性变。它还可以促进雌激素的产生。
In the traditional diet, rather than just eating muscle meats, all the animal parts were used. Since collagen makes up about 50% of the protein in an animal, and is free of tryptophan, this means that people were getting about half as much tryptophan in proportion to other amino acids when they used foods such as “head cheese,” ox-tails, and chicken feet. 在传统饮食中，不只是吃肌肉，所有的动物部位都被使用。由于胶原蛋白约占动物蛋白质的50%，而且不含色氨酸，这意味着当人们食用“头芝士”、牛尾和鸡爪等食物时，色氨酸与其他氨基酸的比例大约是原来的一半。
While some of the toxic effects of an excess of individual amino acids have been investigated, and some of the protective or harmful interactions resulting from changing the ratios of the amino acids have been observed, the fact that there are about 20 amino acids in our normal diet means that there is an enormous number of possibilities for harmful or beneficial interactions. 虽然已经研究了过量的单个氨基酸的一些毒性作用，也观察到了由于改变氨基酸比例而产生的一些保护性或有害的相互作用，事实上，在我们的日常饮食中大约有20种氨基酸，这意味着存在着大量有害或有益的相互作用的可能性。
The optimal quantity of protein in the diet has traditionally been treated as if it were a matter that could be resolved just by observing the rate of growth when a certain protein is given in certain quantities, along with “standard amounts” of calories and other nutrients. This kind of research has been useful to farmers who want to find the cheapest foods that will produce the biggest animals in the shortest time. But that kind of research climate has spread a degraded concept of nutrition into the culture at large, influencing medical ideas of nutrition, the attitudes of consumers, and the policies of governmental regulatory agencies. 传统上，人们一直认为，饮食中蛋白质的最佳数量，似乎只要观察特定数量的蛋白质以及“标准数量”的卡路里和其他营养物质的生长速度，就能解决这个问题。这种研究对那些想要在最短时间内生产出最大动物的最便宜食物的农民很有用。但是，这种研究氛围已经把一种退化的营养概念传播到整个文化中，影响了营养的医学观念、消费者的态度和政府监管机构的政策。
When synthetic amino acids are used to supplement natural proteins, they are usually chosen according to irrelevant models of the “ideal protein's” composition, and many toxic contaminants are invariably present in the synthetic free amino acids. 当合成氨基酸用于补充天然蛋白质时，它们通常是根据“理想蛋白质”组成的无关模型来选择的，而且许多有毒污染物总是存在于合成的游离氨基酸中。
For the present, the important thing is to avoid the use of the least appropriate food products, while choosing natural foods that have historical, epidemiological, and biochemical justification. 就目前而言，重要的是避免使用最不合适的食品产品，同时选择具有历史、流行病学和生化理由的天然食品。
Whey has been promoted as a protein supplement, but it contains a slightly higher proportion of tryptophan than milk does. Cheese (milk with the whey removed) contains less tryptophan. Some people have been encouraged to eat only the whites of eggs, “to avoid cholesterol,” but the egg albumin is rich in tryptophan. 乳清被推广为蛋白质补充剂，但它所含色氨酸的比例比牛奶略高。奶酪(除去乳清的牛奶)含有较少的色氨酸。有些人被鼓励只吃蛋清，“以避免胆固醇”，但蛋清富含色氨酸。
The expensive tender cuts of meat contain excessive amounts of cysteine and tryptophan, but bone broth (gelatin) and the tougher cuts of meat contain more gelatin, which lacks those amino acids. Many fruits are deficient in tryptophan, yet have very significant quantities of the other amino acids. They also contain some of the “carbon skeleton” (keto-acid) equivalents of the essential amino acids, which can be converted to protein in the body. 昂贵的嫩肉块含有过量的半胱氨酸和色氨酸，但骨汤(明胶)和较硬的肉块含有更多的明胶，而明胶缺乏这些氨基酸。许多水果缺乏色氨酸，但其他氨基酸的含量却非常高。它们还含有一些必需氨基酸的“碳骨架”(酮酸)，可以在体内转化为蛋白质。
Serotonin excess produces a broad range of harmful effects: Cancer, inflammation, fibrosis, neurological damage, shock, bronchoconstriction, and hypertension, for example. Increased serotonin impairs learning, serotonin antagonists improve it. 血清素过量会产生广泛的有害影响:例如癌症、炎症、纤维化、神经损伤、休克、支气管收缩和高血压。增加会损害学习能力，血清素拮抗剂会改善学习能力。
The simplest, nonessential, amino acid, glycine, has been found to protect against carcinogenesis, inflammation, fibrosis, neurological damage, shock, asthma, and hypertension. Increased glycine improves learning (Handlemann, et al., 1989; File, et al., 1999), glycine antagonists usually impair it. Its antitoxic and cytoprotective actions are remarkable. Collagen, besides being free of tryptophan, contains a large amount of glycine–32% of its amino acid units, 22% of its weight. 最简单的、非必需的氨基酸，甘氨酸，已被发现可以预防癌变、炎症、纤维化、神经损伤、休克、哮喘和高血压。增加甘氨酸可改善学习(Handlemann等，1989;文件，等，1999)，甘氨酸拮抗剂通常损害它。其抗毒性和细胞保护作用显著。胶原蛋白除了不含色氨酸外，还含有大量的甘氨酸——占其氨基酸单位的32%，占其重量的22%。
The varied antiinflammatory and protective effects of glycine can be thought of as an antiserotonin action. For example, serotonin increases the formation of TNF (tumor necrosis factor, also called cachectin), glycine inhibits it. In some situations, glycine is known to suppress the formation of serotonin. Antagonists of serotonin can potentiate glycine's effects(Chesnoy-Marchais, et al., 2000). People who ate traditional diets, besides getting a lower concentration of tryptophan, were getting a large amount of glycine in their gelatin-rich diet. 甘氨酸的多种抗炎和保护作用可以被认为是一种抗血清素的作用。例如，血清素增加TNF(肿瘤坏死因子，也称为cachectin)的形成，甘氨酸则抑制它。在某些情况下，甘氨酸可以抑制血清素的形成。血清素拮抗剂可增强甘氨酸的作用(Chesnoy-Marchais等，2000年)。吃传统饮食的人，除了得到较低浓度的色氨酸，还从富含明胶的饮食中得到大量的甘氨酸。
Gelatin, besides being a good source of glycine, also contains a large amount of proline, which has some antiexcitatory properties similar to glycine. 明胶除了是甘氨酸的良好来源外，还含有大量的脯氨酸，脯氨酸具有与甘氨酸相似的抗兴奋性。
If a half-pound of steak is eaten, it would probably be reasonable to have about 20 grams of gelatin at approximately the same time. Even a higher ratio of gelatin to muscle meat might be preferable. 如果吃了半磅牛排，大约在同一时间摄入大约20克明胶是合理的。甚至更高的明胶与肌肉肉的比例可能是更好的。
Carbon dioxide, high altitude, thyroid, progesterone, caffeine, aspirin, and decreased tryptophan consumption protect against excessive serotonin release. When sodium intake is restricted, there is a sharp increase in serotonin secretion. This accounts for some of the antiinflammatory and diuretic effects of increased sodium consumption–increasing sodium lowers both serotonin and adrenalin. 二氧化碳、高海拔、甲状腺、黄体酮、咖啡因、阿司匹林和色氨酸摄入的减少可以防止过量的血清素释放。当钠摄入量受到限制时，血清素分泌会急剧增加。这就解释了增加钠摄入量的一些抗炎和利尿作用——增加钠摄入量可以降低血清素和肾上腺素。
The polyunsaturated oils interact closely with serotonin and tryptophan, and the short and medium chain saturated fatty acids have antihistamine and antiserotonin actions. Serotonin liberates free fatty acids from the tissues, especially the polyunsaturated fats, and these in turn liberate serotonin from cells such as the platelets, and liberate tryptophan from serum albumin, increasing its uptake and the formation of serotonin in the brain. Saturated fats don't liberate serotonin, and some of them, such as capric acid found in coconut oil, relax blood vessels, while linoleic acid constricts blood vessels and promotes hypertension. Stress, exercise, and darkness, increase the release of free fatty acids, and so promote the liberation of tryptophan and formation of serotonin. Increased serum linoleic acid is specifically associated with serotonin-dependent disorders such as migraine. 多不饱和脂肪酸与血清素和色氨酸相互作用密切，短链和中链饱和脂肪酸具有抗组胺和抗血清素的作用。血清素从组织中释放出游离脂肪酸，尤其是多不饱和脂肪，而这些脂肪酸又从血小板等细胞中释放出血清素，从血清白蛋白中释放出色氨酸，增加了色氨酸的摄取，并促进了大脑中血清素的形成。饱和脂肪不能释放血清素，其中一些，如椰子油中发现的癸酸，可以放松血管，而亚油酸会收缩血管，促进高血压。压力、运动和黑暗，增加了游离脂肪酸的释放，从而促进了色氨酸的释放和血清素的形成。血清亚油酸增加与血清素依赖性疾病如偏头痛有关。
Coconut oil, because of its saturated fatty acids of varied chain length, and its low linoleic acid content, should be considered as part of a protective diet. 椰子油由于其饱和脂肪酸链长不同，亚油酸含量低，应考虑作为保护性饮食的一部分。
In the collagen theory of aging, it is argued that changes in the extracellular matrix are responsible for isolating cells from their environment, reducing the availability of nutrients and oxygen, and reducing their ability to send and receive the chemical signals that are needed for correct adaptive functioning. 衰老的胶原蛋白理论认为，细胞外基质的变化导致细胞脱离环境，减少营养和氧气的可用性，降低细胞发送和接收化学信号的能力，而这些化学信号是正确的适应功能所必需的。
In diabetes, basement membranes are thickened, and in a given volume of tissue there are fewer capillaries. This effect probably involves excessive serotonin(Kasho, et al., 1998). Old animals contain a higher proportion of collagen. Old tendons (or tendons that have been exposed to excessive estrogen, which stimulates the formation of collagen) are more rigid, and behave almost as if they have been partly cooked. In diseases such as carcinoid, in which very large amounts of serotonin are released systemically, fibrosis is exaggerated, and may be the direct cause of death. Radiation and oxygen deprivation also lead to increased tissue fibrosis. 糖尿病患者基底膜增厚，在一定体积的组织中毛细血管较少。这种影响可能涉及过量的血清素(Kasho等，1998)。年老的动物含有更高比例的胶原蛋白。旧的肌腱(或暴露在过量雌激素下的肌腱，刺激胶原蛋白的形成)更硬，表现得几乎就像被部分煮熟了一样。在像类癌这样的疾病中，全身释放大量血清素，纤维化加剧，可能是直接导致死亡的原因。辐射和缺氧也会导致组织纤维化加剧。
In specific fibrotic conditions, such as cirrhosis of the liver, it is known that glycine and saturated fats can reverse the fibrosis. In fibrosis of the heart, thyroid hormone is sometimes able to reverse the condition. 在特定的纤维化情况下，如肝硬化，众所周知甘氨酸和饱和脂肪可以逆转纤维化。在心脏纤维化中，甲状腺激素有时能扭转病情。
I think these facts imply that excessive tryptophan, estrogen, and polyunsaturated fats contribute significantly, maybe decisively, to the degenerative changes that occur in aging. Experiments have separately shown that reducing dietary tryptophan or unsaturated fats can extend the healthy lifespan, and several antiestrogenic interventions (removal of the pituitary, or supplementing with progesterone) can slow age-related changes and delay degenerative diseases. Since these factors interact, each tending to promote the others, and also interact with exogenous toxins, excess iron accumulation, and other stressors, it would be reasonable to expect greater results when several of the problems are corrected at the same time. 我认为这些事实表明，过量的色氨酸、雌激素和多不饱和脂肪对衰老过程中发生的退行性变化起着重要的，也许是决定性的作用。单独的实验表明，减少饮食中的色氨酸或不饱和脂肪可以延长健康的寿命，几种抗雌激素干预(去除脑垂体或补充孕酮)可以延缓与年龄相关的变化和延缓退行性疾病。由于这些因素相互作用，每个因素都倾向于促进其他因素，而且还与外源毒素、过量的铁积累和其他压力源相互作用，因此，当几个问题同时得到纠正时，预期会产生更大的结果是合理的。
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