Are seasonal vegetables more nutritious than off-season vegetables?

Vegetables are an important source of vitamins, minerals, dietary fiber and nutrients such as plant compounds and play an important role
in our daily dining table.
But vegetables that can be eaten all year round have aroused people's doubts, believing that eating off-season vegetables is not conducive to human health, so how can we correctly understand off-season vegetables?

What are off-season vegetables?

To figure out whether off-season vegetables are good or not, you must first figure out the definition of
off-season vegetables.
Seasonal vegetables refer to dishes that are grown, grown and matured according to natural environmental and climatic conditions such as seasons and solar terms, also known as seasonal vegetables
.

Off-season vegetables are usually divided into three categories according to the planting and growth:

1.
Off-site planting
.
That is, it is planted and grown in the southern region and transported to the northern market in winter; This type of vegetable is a seasonal dish for the south and an off-season dish for the north, such as cabbage and pea tips
.

2.
Long-term storage
.
That is, to extend the shelf life of seasonal vegetables through modern technologies (such as low-temperature storage), such as garlic and so on
.

3.
Vegetables
grown in greenhouses.
To be precise, the first two are not considered off-season vegetables, because they are in season for the place of production, but they are out of season
for the place of consumption.
Greenhouse vegetables are what we usually call "unseasonal vegetables"
.

Are seasonal vegetables more nutritious than off-season vegetables?

1.
Generally speaking, seasonal vegetables are richer in nutrition and have higher
nutritional value than off-season vegetables.

The content of vitamin C, soluble sugar and minerals in seasonal vegetables was significantly higher than that of out-of-season vegetables
.
For example:

Seasonal cucumbers contain 0.
75 mg of chlorophyll, 16.
2 mg of vitamin C and 2.
3 mg of sugar per 100 grams, while cucumbers grown in season contain 0.
36 mg of chlorophyll, 12.
7 mg of vitamin C and 1.
7 mg of sugar per 100 grams, which is lower than that of cucumbers
grown in season.

Peppers and tomatoes contained 149 mg and 33.
6 mg of vitamin C per 100 grams planted in season, while peppers and tomatoes planted out of season contained only 85.
2 mg and 14.
3 mg
of vitamin C per 100 grams, respectively.

The protein, potassium, calcium, iron and other nutrients of vegetables grown out of season are also lower than those of vegetables grown in season
.

2.
Seasonal vegetables are mostly planted in the open field, and the conditions such as ventilation and sunshine are better
.

This is due to the fact that seasonal vegetables are planted in the open, good ventilation, sufficient sunshine and the temperature difference between day and night, so that the synthesis and accumulation of nutrients are more abundant, and the fruits are full and juicy; Off-season vegetables are mostly grown in greenhouses, which are limited by the light and temperature in the greenhouse, and the relative accumulation of nutrients is small, and the taste is also affected
.

3
.
The use of pollution-free organic fertilizers improves the quality of off-season vegetables.

China's northern winter and spring are cold, crop planting is limited, seasonal vegetables are single, mainly cabbage, radish, while beans, nightshades, dark leafy vegetables and other vegetables rich in protein, vitamin B2, carotene are few, resulting in unbalanced
nutrient supply.

In order to extend the consumption period of winter vegetables, northern residents often store or pickle vegetables
.
Long-term storage and pickling of fresh vegetables, especially leafy vegetables, will not only cause the loss of original nutrients, but also increase the content of nitrate and nitrite in vegetables, affecting people's health
.

Although the nutrient content of off-season vegetables is slightly inferior to that of the same seasonal vegetables, it can still make up for the nutrient deficiencies caused by a single vegetable variety in winter and spring, and play an important role
in reasonable diet.

And with the use of pollution-free organic fertilizer, the content of vitamin C, soluble sugar, protein and organic acids in off-season vegetables increases, the nitrate content decreases, and the nutritional quality of off-season vegetables is improved
.

How to choose vegetables in daily life?

When selecting vegetables daily, seasonal vegetables should be the main ones to ensure the nutrition and safety of vegetables ingested by the human body; In the season when vegetable types are scarce, seasonal vegetables should be matched with off-season vegetables to ensure the balance of human intake
.

It is recommended to consume 300-500 grams of vegetables per day, and dark vegetables account for more than
half.

Text/Li Muxia (Dr.
Ma Health Group)