虾青素与花青素

【叶子按语：读了一些资料，收集在此，总结如下。个人觉得花青素可以从所提到的蔬菜水果中摄取，即使无效，也有益无害。至于虾青素，痛风病人不能直接从海鲜食品中摄取，是否长期服用从藻类中提取的保健品还是个值得商榷的问题。】


谈到痛风，就谈到嘌呤、谈到尿酸，那么尿酸是怎么形成的呢？

核酸是一种高分子化合物，核酸是由无数的核苷酸组成。每一个核苷酸都由三部分组成，一个磷酸分子、一个戊糖(五碳糖)和一个碱基（嘌呤或嘧啶）。生物细胞核中的遗传物质 DNA （脱氧核糖核酸）和细胞质中RNA（核糖核酸）由几十万、几百万甚至几千万个核苷酸组成。反过来当核酸氧化分解后的产物之一就是嘌呤，所以说嘌呤是细胞的组成成分。

体内的老旧细胞，还有食物，尤其是富含嘌呤的食物（如动物内脏、海鲜等）在体内新陈代谢过程中，其核酸氧化分解产物就有嘌呤（这种内源性的嘌呤占总嘌呤的80%）。体内产生嘌呤后，会在肝脏中再次氧化为2，6，8--三氧嘌呤，又称为尿酸。

2/3尿酸经肾脏随尿液排出体外，1/3通过粪便和汗液排出。可见，嘌呤是核酸的氧化分解的代谢产物，而尿酸是嘌呤的代谢最终产物，其中的嘌呤环没有解开。

根据尿酸产生的机理，我们反过来推导：要防治好痛风就要减少尿酸的产生，要减少尿酸的产生就要减少体内的嘌呤，减少体内的嘌呤就要减少核酸的氧化分解和嘌呤的摄入，同时加强尿酸的排除。

其中，防止细胞内核酸的氧化分解是重头戏，主要的方法就是服用一些抗核酸氧化的物质，比如说虾青素、花青素之类。做好了这条就可以减少80%的内源性嘌呤的产生。


花青素（Anthocyanidins）的来源：

7 Foods Rich in Anthocyanidins

A number of fruits and vegetables have high amounts of anthocyanidins in them. You can most easily spot these powerful antioxidant foods by their bright colors. Here are some of the top anthocyanidin-rich foods on the menu. 

Blueberries – These tiny berries, often eaten on cereal, in baked goods, or with yogurt, carry a powerful blend of anthocyanidins and other antioxidants under their indigo skins. 

Red and Black Grapes – Various varieties of grapes also contain a lot of anthocyanidins. This makes wine a potential health booster in moderation. Jams and jellies also carry the same antioxidants, but with a lot of sugars, which can add some unwanted calories to a meal. Fresh grapes are always a good recommendation. 

Cranberries – These sour berries include a good serving of anthocyanidins. However, many cannot stomach the cranberry without some additional sugar or other complementary flavors. Try a cranberry blend drink, a cranberry sauce or other concoction to use these strongly flavored berries in your diet. 

Raspberries and Blackberries – These colorful berries loaded up with anthocyanidin pigmentation are also a great source of antioxidants, especially when they are in season. 

Red Cabbage – The bright color of red cabbage reflects its high anthocyanidin value. Try this shredded in soups, salads or other dishes. 

Red Onions – These versatile vegetables give flavor to sandwiches, soups, salads and pasta dishes. A good reason to use these for anthocyanidin value is that they are often used raw, where the strength of certain chemicals can be reduced by cooking fruits and vegetables. 

Eggplant – This purple giant of the garden is also a anthocyanidin-rich food. For the best nutritional value, consider roasting the eggplant whole, or using it in another way that includes eating the skin, where antioxidants are located.

虾青素（Astaxanthin）的来源：

虾青素是一种天然抗氧化剂，是一种类胡萝卜素，呈粉红色，广泛存在于生物界，特别是虾、蟹、鱼、藻体、酵母和鸟类的羽毛中含量较高。由于鱼虾蟹及藻类是含有高嘌呤的食品，痛风病人应禁食，所以虾青素主要从保健品摄取。

资料显示利用化学手段合成虾青素时将不可避免的引入杂质化学物质，如合成过程中产生的非天然副产物等，将降低其生物利用安全性 。

随着天然虾青素的兴起，世界各国对化学合成虾青素的管理也越来越严，如美国食品与药物管理局(FDA)已禁止化学合成的虾青素进入食品与膳食补充剂（Supplements）市场，而天然虾青素在FDA取得了一般性安全认证（GRAS），能够合法的进入食品与膳食补充剂市场。

虾青素的生产一般倾向于开发天然虾青素的生物(植物)来源，并由此进行大规模生产。有能力商业化养殖雨生红球藻生产天然虾青素的公司逐渐兴起。调研结果显示有代表性的为：美国Cyanotech、日本富士化工、以色列Algatech、中国云南石林的云彩金可（GingkoAsta）与爱生行（AstaBiotec） 。

Cyanotech 生产的虾青素制品：

BioAstin® Natural Astaxanthin is the world's best selling brand of astaxanthin for humans. It is a dietary supplement with powerful antioxidant and other health benefits.

Cyanotech produces BioAstin from microalgae. It was the first source of astaxanthin for human nutrition reviewed by the U.S. Food and Drug Administration (FDA). In August 1999, BioAstin completed a review by the FDA without objection and was allowed to be sold in the United States as a dietary supplement.

BioAstin's benefits derive from its superior antioxidant activity and from its ability to fight free radical damage and combat ongoing oxidative stress, supporting skin, muscle and joint health.

Natural Astaxanthin can have up to 550 times the antioxidant activity of vitamin E and 10 times the antioxidant activity of beta-carotene, and surpasses many of the antioxidant benefits of Vitamin C and other carotenoids*.

http://www.cyanotech.com/bioastin.html