There has been so much about coffee in the news these past few months. A number of significant studies have look at its effects on reducing everything from heart disease, cancer and diabetes. Here's what you need to know. 

The Health Benefits of Coffee

There's been a number of reviews around studies that have cited the benefits of various aspects of drinking coffee. Most studies recognize a "cup of coffee" being an 8 ounce serving and when we talk about coffee, we mean black coffee, not with milk, sugar, syrup and other additives. Across the board of most studies, 3-4 cups per day for most everyone is where the peak benefit can be traced to.  Pregnant women and those who suffer from acid reflux and other issues should stay away.

Black coffee has reported the following benefits:

• Reduce risk of most all types of cardiovascular diseases
• Reduce risk of stroke
• Reduced risk of diabetes
• Reduced overall cancer risk
• Reduce the risk of all liver diseases (liver cancer, cirrhosis etc.)
• Lower risk of Parkinson’s disease
• Reduce risk of cognitive decline
• Potential protective effect against Alzheimer’s

For years, myths like coffee stunts your growth were touted among other, tleading many to believe coffee was not a positive drink of choice. With these new findings, there is no longer a need to view coffee as something we need to cut back on. More research has been done around this morning favorite and has shown potential benefits than almost any other beverage consumed.

So what's in coffee that makes it good for us?

The ingredients that are beneficial are still up for review and in need of more studies. Most of the studies analyzed the number of cups of black coffee consumed in a day that connected to reduced risk of some diseases. 

Researchers are still not concrete on it being solely the caffeine, since coffee contains a host of active substances aside from it that may be the root benefit. For example, coffee has many antioxidants which fight inflammation leading to cancer, heart disease and others. Some studies have found it was chlorogenic acid in coffee that also fights inflammation. 

Coffee for your Brain

New studies show coffee also may improve cognitive function. A meta-analyses on neurological disorders found that coffee intake associated with lower risks of Parkinson’s disease. Participants showed lower cognitive decline and it also showed coffee may be a protective agent against Alzheimer's disease. The study was published in the Journal of Alzheimer's Disease where researchers:

• Measured amount of caffeine in participants by taking blood samples and testing the caffeine plasma levels
• Also tested participants cognitive functioning at start of study and categorized people in 3 categories
  • Normal cognitive functioning: overall memory, judgement and decision making were intact
  • Mild cognitive impairment: Participants displayed some difficulty in cognitive functioning (this usually develops into Alzheimer’s disease
  • Dementia: individual displayed clear impairments in cognition such as memory deficits, communication, judgement

Results:

• Stable cognitive functioning (no cognitive decline) was maintained in those who began the study with normal cognition.
• A lack of progression to dementia occurred in the participants who began the study in the mild cognitive impairment (MCI) category. This is especially notable because there is usually a high rate of progression from MCI to dementia.
• Additionally, a higher rate of progression from mild cognitive impairment to dementia was seen in participants whose caffeine intake was lower.
• The participants' caffeine levels were assumed to come directly from coffee, since they reported no other significant intake of caffeine. A caffeine level of more than 1200 ng/ml is equated with 3 or more cups of coffee a day.

Researchers in a study on mice isolated a component in coffee, Eicosanoyl-5-hydroxytryptamide (EHT), which was given to mice who were engineered to develop to Alzheimer’s disease.

• Mice who initially displayed cognitive impairments as well as buildup of tau protein in their brains this is characteristic
• Improved significantly in both the cleaning of the tau and their cognitive ability after receiving the EHT
• Research is preliminary in mice, does present an interesting possibility for why coffee has been correlated with brain health

Coffee Reduces Cardiovascular Disease

A systematic review and meta-analysis of studies looking at long term consumption of coffee showed it reduced almost all cardiovascular diseases. 

36 studies involving more than 1,270,000 participants combined data showed those who consumed moderate amount of coffee (3-5 cups/day) were at lowest risk for problems.

5 or more cups/day had no higher risk than those who consumed none.

Coffee and Risk of Stroke

Another meta-analysis of studies also showed coffee may reduce risk of stroke. Researchers looked at how coffee consumption might be associated with stroke.  11 studies were found with 480,000 participants. Researchers found a peak at the consumption of 2-6 cups, which the lowered risk of disease compared with those who drank none.

Coffee and Cancer

Again some of the ingredients like chlorogenic acid and antioxidants are anti-inflammatory agents, which reduce inflammation. This is the leading factor in the progression of most cancers.  

Notable studies:

January 2015: National Cancer Institute published a study showing that people who drank four cups of caffeinated coffee a day had a 20% lower risk of melanoma than non-coffee drinkers.

February 2015: AACR journal found that women who drink four cups a day have a reduced risk of endometrial cancer.

Late March 2015 U.K. researchers released an analysis of 34 studies conducted around the world and concluded that coffee consumption—even just one cup a day—reduces the risk of liver cancer

Scientists still cannot determine what ingredient in coffee stunts tumor growth or reacts with cancer cells. But all these studies are leading us to the root connection.

Caffeine in Coffee May Protect Against Breast Cancer Recurrence

A recent study also showed that as little as  2 cups per day inhibits the growth of tumors and reduced the risk of recurrence in women diagnosed with breast cancer. In this case, they identified that caffeine was the leading ingredient. 

The study was condusted out of Lund University and Skane University Hospital in UK. 

Researchers:

• Combined information about patient’s lifestyle and clinical data
• Studied patients that were treated with Tamoxifen
• Tamoxifen: synthetic drug used to treat breast cancer and infertility in women
  • Acts as an estrogen antagonist
• 1090 breast cancer cancer patients
• Over 500 women that had drank at least two cups/day had only ½ the risk of recurrence verses those who drank no coffee at all
• Those who drank 2 cups/day had smaller tumors and lower proportion of the hormone-dependent tumors

Caffeine and caffeic acid found in coffee react with breast cancer cells and cells reduced, especially in combination with the drug Tamoxifen. Caffeine and the drug have an effect together on the cells and turn off signaling pathways that the cancer cells require to grow.

There has also been previous research that linked breast cancer and coffee. Another study showed that women who drunk more than 5 cups/day may reduce risk of one type of breast: estrogen-receptor positive breast cancer. 

• Swedish study of 6,000 women
• In pre-menopausal women, 4 cups/day has been associated with a 38% lower risk of breast cancer
• For pre-menopausal women at a high risk because they carry the BRCA1 and BRCA2 mutation, the risk for breast cancer is reduced by 25-70% w/consuming 4-6 cups/day (only regular coffee, not decaf)

Reduced risk of liver disease

In patients who have liver disease, coffee associated with decrease progression of cirrhosis. For those who already have cirrhosis, associated with lower risk of death and lower risk of developing liver cancer. They showed improved responses to antiviral therapy in patients with hepatitis C and also showed better outcomes in those with nonalcoholic fatty liver disease

Study authors deemed coffee consumption should be encouraged in those with chronic liver disease.

Reduced risk of diabetes

Diabetes affects millions of people in the U.S. alone. Study authors found that regular coffee consumption is associated with a reduced risk of Type II Diabetes in those who drank at least 6 or 7 cups/day.

A meta-analyses of 28 studies and more than 1.1 million participants measured the consumption of both decaf and regular coffee.