Health Benefits of Broccoli
It’s no wonder that over 300 researches on broccoli have united in one unique area of health issues, the development of cancer, and its connection to the three metabolic issues in the body, viz. 1. Chronic inflammation 2. Insufficient detoxification 3. Oxidative stress. The research of the past 10 years has clearly shown that the risk of cancer in many different organs is connected to the combination of these three problems.
Published: November 20, 2021.
The Connection between Cancer, Inflammation, Detox and Oxidative Stress
In the research going on in health science, more and more evidences are being found of a connection between cancer risk and a series of dietary, environmental and body system factors. Knowing more about this connection can help a lot in understanding the connection between broccoli and health.
When there are high levels of toxins or free radicals in the body, body’s inflammatory system get signals to “kick in” to protect the body from potential harm. A molecule known as Nf-kappaB is a key signaling device. When it senses the dangers described above, it is used to “speed up” the inflammatory response and enhance the creation of inflammatory ingredients (e.g. IL-6, IL-1beta, iNOS, TNF-alpha and COX-2). This system is useful when it’s short-term and there is a need of healing. But when it goes on constantly and indefinitely, it can increase the risk of severe health issues, including the onset of cancer.
Studies have cleared that the NF-kappaB can be considerably suppressed by isothiocyanates (ITCs). ITCs are made from glucosinolates that are found in broccoli and other cruciferous vegetables and in fact help to shut down the system used to form NF-kappaB and other constituents of the inflammatory system.
The main anti-inflammatory ITC in broccoli is sulforaphane. It can be directly formed from the glucoraphanin content in broccoli. Sulforaphane has several anti-inflammatory mechanisms including inactivation of the NF-kappaB pathway. Here it should be remembered that sulforaphane mainly occurs only in the heading version of broccoli, while the “non-heading” or sprouting version of broccoli is used worldwide which is also called broccoli rabe, broccoli raab or rapini. This version of broccoli contains iberin as the most common ITC which is derived from glucoiberin which is one of the more common glucosinolates in non-heading broccoli.
Another anti-inflammatory ingredient present in heading as well as non-heading broccoli is glucobrassicin (the ITC derived from glucobrassicin is indole-3-carbinol).
Omega-3s: Scarcity of omega-3 fatty acids in diet can also cause over-activation of inflammatory system. The reason is easily understandable: several main anti-inflammatory messaging compounds (such as PGH3, LTE5, PGI3 and TXA3) are made of omega-3 fats. While non-fatty vegetables aren’t usually considered to be a source of omega-3 fats, broccoli is an exception. Although the amounts of omega-3s in broccoli are limited, they still play a vital role in making the inflammatory system’s activity balanced. There are around 400 mg omega-3s in the form of ALA (alpha-linolenic acid) in around 2 cups of broccoli. This is equivalent to the amount provided by a flax oil soft-gel capsule. While one cannot depend totally on broccoli for dietary omega-3s, important anti-inflammatory benefits that omega-3s provide can be obtained from broccoli.
Phytonutrients: Broccoli is rich in a specific phytonutrient (a flavonol) known as kaempferol which has the power to reduce the effect of allergy-related substances (by reducing the production of IgE-antibodies by the immune system). Thus by reducing the effect of allergy-related substances, the kaempferol in broccoli can help reduce the risk of chronic inflammation.
Phytonutrients, vitamins and minerals in the food provide antioxidant benefits. Broccoli provides all these three antioxidants. It’s the best source of vitamins A (in the form of carotenoids), C and E. It is also an excellent source of chromium, selenium, manganese and zinc. But broccoli’s antioxidant benefits stand out truly with its phytonutrient contents. Broccoli has high concentrations of flavonoids like quercitin, kaempferol, and carotenoids like zeaxanthin, beta-carotene and lutein.
Broccoli sprouts are not consumed in the US as often as pea sprouts, mung bean and alfalfa; but they are widely consumed in other countries. These are rich sources of antioxidants.
Human body continuously collects toxins which should be cleared from the body to save the body from the risk of cell damage. The isothiocyanates (ITCs) produced from the glucosinolates in broccoli have been constantly proved to enhance detoxification ability. A lot of studies on broccoli have focused on a component in the detoxification process known as Phase 2 wherein active toxic substances get attached to nutrients and are excreted from the body. The glucosinolates in broccoli (and their isothiocyanate derivatives) are proven to induce Phase 2 detox activity in cells.
The exclusive combination of anti-inflammatory, antioxidant and pro-detoxification ingredients in broccoli make it a prized food when it comes to cancer prevention. Relations between onset of cancer and chronic inflammation, oxidative stress and insufficient detoxification are so well-established by studies that any food enhancing all three of these metabolic issues would have a high ability to reduce the risk of cancer. In the case of broccoli, there is a strong research showing a reduced risk of colon cancer, ovarian cancer, prostate cancer, bladder cancer and breast cancer with regular consumption of broccoli.
There are two basic types of digestive support provided by broccoli: ITC (Isothiocyanate) support and fiber support. At around 1 gram of dietary fiber per 10 calories, one doesn’t have to eat a lot of broccoli to obtain a large amount of the daily requirement. For 100 calories only 5% of a 2000-calorie diet, one gets around 10 grams of fiber or 40% of the DV (Daily Value). And 250 calories of broccoli (around 12% of a 2000-calorie diet) can provide a person the full daily requirement of fiber. There are only a few nutrients that support the digestive system as efficiently as fiber.
Glucosinolates in broccoli on the other hand are phytonutrients that are converted by the body into ITCs (isothiocyanates). ITCs, especially sulforaphane, help protect the stomach lining by preventing bacterial proliferation of H. pylori.
Recent researches have shown that eating broccoli can lower the levels of LDL-cholesterol in the blood. One of the most recent studies showed a reduction of LDL-cholesterol by around 2.5% after eating 1/3 cups of broccoli every day for 3 months. Both raw as well as steamed broccoli offer the same LDL-reduction benefits. However, steamed broccoli has been found more effective than raw broccoli in LDL-reduction.
However, there is a major transition of thinking going on about the role of LDL reduction for our health. E.g. a study has found that people with high LDL-cholesterol levels tend to live as long as or even longer than those with average or low levels of LDL.
While it’s definitely agreed that broccoli offers cardiovascular benefits, the reasons for those benefits are being considered to be more due to reduced oxidative stress and control of inflammation, and less due to cholesterol management.
Another component of broccoli, i.e. B-complex vitamins, is also a major contributor to cardiovascular benefits. Particularly regarding overly production of homocysteine (hyperhomocysteinemia), a phenomenon which increases the risk of atherosclerosis, heart attack and stroke, B-complex deficiency can pose a major risk. Especially three B vitamins, viz. B6, B12 and folate are important for reducing the risk of hyperhomocysteinemia, and daily intake of 1.66 cups of steamed broccoli for just 10 days has been shown to increase blood folate levels in a study on cigarette smokers (given below). Thus by increasing the B6 and folate levels in one’s body, broccoli can help significantly in lowering the risk of homocysteine formation and the associated cardiovascular issues.
Broccoli has a significant amount of two carotenoids, zeaxanthin and lutein, that play an important part in the eye health. Actually no other tissue in the body has more concentration of lutein than in the outer portion of retina (known as peripheral retina). Similarly zeaxanthin is intensely concentrated in the macula near the middle part of retina. Problems with lens area (e.g. cataracts) and macula (e.g. macular degeneration) have been found to be reduced with intake of foods (including broccoli) that offer large amounts of zeaxanthin and lutein carotenoids.
Recent Studies on Broccoli Health Benefits
Broccoli is gaining popularity as a health food. The method of cooking broccoli has also an important role to play in its health-giving properties. Quick steaming has been the most recommended way of cooking broccoli. This is supported by numerous recent studies that show how steaming of broccoli offers so many nutritional benefits (as against other cooking techniques). These benefits include better retention of vitamin C and sulforaphane when broccoli is steamed instead of boiled. These studies also note higher firmness and brighter green color due to short-term steaming as compared to long-term steaming. Here short-term typically means 5 minutes or even less and long-term means more than 5 minutes, and often more like 15-20 minutes.
The difference in the concentration of nutrients has also been clearly observed in these recent studies when steaming time is changed by relatively small amounts. For example, researchers have compared nutrient concentration in broccoli steamed for 1 against 2 minutes or 3 against 5 minutes. Several nutrients in broccoli are obviously sensitive to total steaming time, and on an average, all studies recommend that total steaming time should be kept relatively short. Ideally broccoli leaves and florets should be steamed for 4 minutes.
Broccoli has sulfur compounds that have anti-inflammatory benefits and have strong research track record. A recent study has been added to this track record showing benefits of broccoli in a small group of smokers who smoked at least 10 cigarettes per day on an average. Participants were given around 1.66 cups of steamed (for 10 minutes) broccoli for 10 days and they showed a fall in their level of C-reactive protein (CRP) in blood. CRP is a protein used to gauge the degree of inflammation. There was also an increase in the levels of B-vitamin folate and carotenoid lutein in participants’ blood.
Another recent study on organically grown broccoli showed a connection between the deep green coloration of broccoli florets and their total amount of carotenoid. This means that the deeper and richer the green color of the florets, the more will be the carotenoids they contain. As carotenoids are yellowish orange in color and don’t impart greenness to foods, this observation is a bit surprising.
However, it also gives health enthusiasts a practical way to make their broccoli selection if they want broccoli with higher amount of carotenoid.
How to Cook Broccoli to Retain its Nutrients?
Studies show that even children love broccoli and a definite way to enjoy it is to cook it correctly i.e. by quick steaming. If broccoli is overcooked, it becomes soft and mushy, and also loses nutrients as well as flavors.
A correct way to cook broccoli is to first cut broccoli florets in quarters and keep aside for many minutes before cooking to improve their health-promoting benefits. Then they should be steamed for 4 minutes.
Broccoli should be included as one of the cruciferous vegetables that users eat regularly if they want to get benefits offered by the cruciferous vegetable family.
How Much to Consume?
It has been observed in studies that an average of ½ cup of broccoli every day (only 22 calories) is adequate to offer some considerable benefits. However, a 2-cup serving twice a week could also suffice the minimum amount. But studies also show that more amount of broccoli might be required to start cancer-preventing processes. This is around 1.6 cups of broccoli per day. A study has also shown that high amounts of broccoli can help optimize the amounts of antioxidants, particularly lutein and beta-carotene in the blood. In this study, the term “high” denotes 3 cups daily.
As such, broccoli is safe to eat and has no serious side effects. The most common side effect is bowel irritation or gas resulting from the high amounts of fiber in broccoli. This is a characteristic of all cruciferous vegetables that they can make you gassy; however, their benefits overshadow the discomfort.
As per the Ohio State University Wexner Medical Center, those who are on blood-thinning medications should eat broccoli carefully as the high amount of vitamin K in broccoli can interfere with the effectiveness of the medication.
Also hypothyroidism patients should limit their broccoli consumption.
All in all, broccoli is a storehouse of nutrients and those who want to be healthy should essentially include this vegetable in their diet.