植物营养素 What Are Phytonutrients?

植物类食物含有数千种天然化学物质。这些被称为植物营养素或植物生化素。 “Phyto”是指植物的希腊词。这些化学物质有助于保护植物免受细菌、真菌、昆虫和其他危害。水果和蔬菜含有植物营养素。其他植物性食物也含有植物营养素，例如：

• 全谷类
• 坚果
• 豆类
• 茶

与植物类食物中所含的维生素和矿物质不同，植物营养素并不是维持生命的所需的。但是当你食用或饮用植物营养素时，它们可能有助于预防疾病并保持身体正常运作。

植物类食物中含有超过25,000种植物营养素。 让我们了解六种重要的植物营养素 – 以及它们对健康的潜在影响：

• 类胡萝卜素
• 鞣花酸
• 黄酮
• 白藜芦醇
• 硫代葡萄糖苷
• 植物雌激素

类胡萝卜素

超过600种类胡萝卜素给予水果和蔬菜提供黄色、橙色和红色。类胡萝卜素可以作为体内的抗氧化剂。这意味着它们可以对抗损害整个身体组织的有害自由基。可能具有其他健康益处的类胡萝卜素类型包括：α-胡萝卜素、β-胡萝卜素和β-隐黄质。你的身体可以将它们转化为维生素A。这种维生素有助于保持你的免疫系统正常运作，这对眼睛的健康是必需的。黄色和橙色类食物如南瓜和胡萝卜等是α-胡萝卜素和β-胡萝卜素极佳来源，亦还含有β-隐黄素，甜红辣椒也是如此。

番茄红素。

给予以下食物红色或粉红色：

• 番茄
• 西瓜
• 粉红葡萄柚

番茄红素与前列腺癌风险较低有关。

叶黄素和玉米黄质。

这些可能有助于保护您免受白内障和年龄相关的黄斑变性，这两种都是眼部问题。这些植物营养素的良好来源是绿色，如：

• 菠菜
• 羽衣甘蓝
• 宽叶羽衣甘蓝

鞣花酸

鞣花酸存于许多莓果和其他植物性食物中，尤其是：

• 草莓
• 山莓
• 石榴

鞣花酸可以通过几种不同的方式帮助预防癌症。例如，它可以减缓癌细胞的生长。它可能有助于您的肝脏中和您系统中的致癌化学物质。但这种酸的研究主要是在实验室进行的，因此它对人类健康的益处是未知的。

黄酮类化合物

大量的植物营养素属于类黄酮类。它们存在于各种植物类食物中。黄酮类类型包括：

儿茶素。

绿茶是儿茶素的特佳来源。这种饮料可能有助于预防某些癌症。

橙皮苷。

这种黄酮类化合物存在于柑橘类水果，可减少体内炎症，有助与预防慢性疾病。

黄酮。

槲皮素是一种经过充分研究的黄酮醇类型。它发现于：

• 苹果
• 浆果
• 羽衣甘蓝
• 洋葱

它有助于降低哮喘、某些癌症和冠心病的风险。

白藜芦醇

白藜芦醇存在于：

• 葡萄
• 紫葡萄汁
• 红酒

它具有抗氧化和抗炎作用。一些研究表明，白藜芦醇可能发挥降低患心脏病和某些癌症方面的风险。动物研究表明，它可能有助于延长寿命。但需要更多的人类研究来建立明确的关系。

硫代葡萄糖苷

十字花科蔬菜中含有硫代葡萄糖苷，包括：

• 布鲁塞尔菜苗 (抱子甘藍)
• 包心菜
• 羽衣甘蓝
• 西兰花

硫代葡萄糖苷为这些蔬菜提供了鲜美的气味和味道。在烹饪过程中或当你消化这些食物时，硫代葡萄糖苷会变成其他化学物质。这些化学物质可能有助于控制癌症的发展和生长。

植物雌激素

由于它们的结构，植物雌激素可以发挥类似雌激素的作用。它们还可以阻止您自然供应雌激素的影响。大豆食品含有异黄酮 – 一种植物雌激素。一些证据表明，大豆食品可能与以下因素有关：

• 降低子宫内膜癌的风险
• 降低女性骨质流失的风险

你的身体将木脂素（另一种植物营养素）转化为具有类似雌激素作用的化学物质。两种特别好的木脂素来源是：

• 亚麻种子
• 芝麻籽

然而，支持木脂素在预防子宫内膜癌或骨质疏松症中的作用研究是有限的。资料

来源: https://www.webmd.com/diet/guide/phytonutrients-faq#1

Plant foods contain thousands of natural chemicals. These are called phytonutrients or phytochemicals. “Phyto” refers to the Greek word for plant. These chemicals help protect plants from germs, fungi, bugs, and other threats.Fruits and vegetables contain phytonutrients. Other plant-based foods also contain phytonutrients, such as:

• Whole grains
• Nuts
• Beans
• Tea

Phytonutrients aren’t essential for keeping you alive, unlike the vitamins and minerals that plant foods contain. But when you eat or drink phytonutrients, they may help prevent disease and keep your body working properly.

More than 25,000 phytonutrients are found in plant foods. Lets take a look at these six important phytonutrients — and their potential health effects:

• Carotenoids
• Ellagic acid
• Flavonoids
• Resveratrol
• Glucosinolates
• Phytoestrogens

Carotenoids

More than 600 carotenoids provide yellow, orange, and red colours in fruits and vegetables.

Carotenoids act as antioxidants in your body. This means they tackle harmful free radicals that damage tissues throughout your body.

The types of carotenoids that may have other health benefits include:

Alpha-carotene, beta-carotene, and beta-cryptoxanthin. Your body can convert all of these to vitamin A. This vitamin helps keep your immune system working properly, and it’s needed for eye health. Yellow and orange foods like pumpkins and carrots are good sources of alpha- and beta-carotene.

These also contain beta-cryptoxanthin, as do sweet red peppers.

Lycopene.

This gives red or pink colour to:

• Tomatoes
• Watermelon
• Pink grapefruit

Lycopene has been linked to a lower risk of prostate cancer.

Lutein and zeaxanthin. These may help protect you from cataracts and age-related macular degeneration, which are two types of eye problems.

Good sources of these phytonutrients are greens such as:

• Spinach
• Kale
• Collards

Ellagic Acid

Ellagic acid is found in a number of berries and other plant foods, especially:

• Strawberries
• Raspberries
• Pomegranates

Ellagic acid may help protect against cancer several different ways. For example, it may slow the growth of cancer cells. And it may help your liver neutralize cancer-causing chemicals in your system. But studies of this acid have mainly been done in the laboratory, so its benefits for human health is an unknown.

Flavonoids

A large number of phytonutrients fall into the flavonoid category. They are found in a variety of plant foods.

The types of flavonoids include:

Catechins.

Green tea is an especially good source of catechins. The drink may help prevent certain types of cancer.

Hesperidin.

Found in citrus fruits, this flavonoid works as an antioxidant reducing inflammation in the body to help prevent chronic disease.

Flavonols.

Quercetin is a well-studied type of flavonol. It is found in:

• Apples
• Berries
• Kale
• Onions

It might help reduce people’s risk of asthma, certain types of cancer, and coronary heart disease.

Resveratrol

Resveratrol is found in:

• Grapes
• Purple grape juice
• Red wine

It acts as an antioxidant and anti-inflammatory.

Some research suggests that resveratrol might play a role in reducing the risk of heart disease and certain cancers. And it may help extend life, animal studies have shown. But more human studies are needed to establish a clear relationship.

Glucosinolates

Glucosinolates are found in cruciferous vegetables, including:

• Brussels sprouts
• Cabbage
• Kale
• Broccoli

They give these vegetables their sharp odours and flavour. The glucosinolates turn into other chemicals during the cooking process and while you digest these foods. These chemicals may help hold in check the development and growth of cancer.

Phytoestrogens

Because of their structure, phytoestrogens can exert estrogen-like effects. They can also block the effects of your natural supply of estrogen.Soy foods contain isoflavones — a type of phytoestrogen. Some evidence suggests that soy foods may be linked to:

• Lower risk of endometrial cancer
• Lower risk of bone loss in women

Your body converts lignans, another type of phytonutrient, into chemicals with some estrogen-like effects. Two especially good sources of lignans are:

• Flaxseeds
• Sesame seeds

However, research supporting a role for lignans in preventing endometrial cancer or osteoporosis is limited.

Source: https://www.webmd.com/diet/guide/phytonutrients-faq#1