Boost your Immune System

What is the immune system?

Your immune system is a complex network of cells, tissues, and organs. Together they help the body fight infections and other diseases.

When germs such as bacteria or viruses invade your body, they attack and multiply. This is called an infection. The infection causes the disease that makes you sick. Your immune system protects you from the disease by fighting off the germs.

What are the parts of the immune system?

The immune system has many different parts, including:

  • Your skin, which can help prevent germs from getting into the body
  • Mucous membranes, which are the moist, inner linings of some organs and body cavities. They make mucus and other substances which can trap and fight germs.
  • White blood cells, which fight germs
  • Organs and tissues of the lymph system, such as the thymus, spleen, tonsils, lymph nodes, lymph vessels, and bone marrow. They produce, store, and carry white blood cells.

How does the immune system work?

Your immune system defends your body against substances it sees as harmful or foreign. These substances are called antigens. They may be germs such as bacteria and viruses. They might be chemicals or toxins. They could also be cells that are damaged from things like cancer or sunburn.

When your immune system recognizes an antigen, it attacks it. This is called an immune response. Part of this response is to make antibodies. Antibodies are proteins that work to attack, weaken, and destroy antigens. Your body also makes other cells to fight the antigen.

Afterwards, your immune system remembers the antigen. If it sees the antigen again, it can recognize it. It will quickly send out the right antibodies, so in most cases, you don’t get sick. This protection against a certain disease is called immunity.

What are the types of immunity?

There are three different types of immunity:

  • Innate immunity is the protection that you are born with. It is your body’s first line of defense. It includes barriers such as the skin and mucous membranes. They keep harmful substances from entering the body. It also includes some cells and chemicals which can attack foreign substances.
  • Active immunity, also called adaptive immunity, develops when you are infected with or vaccinated against a foreign substance. Active immunity is usually long-lasting. For many diseases, it can last your entire life.
  • Passive immunity happens when you receive antibodies to a disease instead of making them through your own immune system. For example, newborn babies have antibodies from their mothers. People can also get passive immunity through blood products that contain antibodies. This kind of immunity gives you protection right away. But it only lasts a few weeks or months.

What can go wrong with the immune system?

Sometimes a person may have an immune response even though there is no real threat. This can lead to problems such as allergies, asthma, and autoimmune diseases. If you have an autoimmune disease, your immune system attacks healthy cells in your body by mistake.

Other immune system problems happen when your immune system does not work correctly. These problems include immunodeficiency diseases. If you have an immunodeficiency disease, you get sick more often. Your infections may last longer and can be more serious and harder to treat. They are often genetic disorders.

There are other diseases that can affect your immune system. For example, HIV is a virus that harms your immune system by destroying your white blood cells. If HIV is not treated, it can lead to AIDS (acquired immunodeficiency syndrome). People with AIDS have badly damaged immune systems. They get an increasing number of severe illnesses.

Medical myths: All about weight loss

1. Skipping breakfast aids weigh loss

The common adage that breakfast is the most important meal of the day may or may not be true, but it seems unlikely that skipping the morning meal aids weight loss.

The rationale behind this strategy is that missing one meal a day leads to a lower overall intake of calories. However, the story is not so straightforward.

One study, published in 2010, analyzed food intake information from 2,184 people aged 9–15 years. Twenty years later, the researchers asked for the same information again.

They compared data from people who had skipped breakfast during childhood and adulthood with data from those who had never skipped breakfast or had done so only in adulthood.

Compared with the other groups, the participants who skipped breakfast during both childhood and adulthood tended to have larger waist circumferences, higher fasting insulin levels, and higher total cholesterol levels.

Sometimes, people who skip breakfast eat more during the rest of the day to counteract the deficit. But one 2013 study

found that missing breakfast does not lead to eating more at lunch. The authors conclude that “Skipping breakfast may be an effective means to reduce daily energy intake in some adults.”

However, these researchers only monitored the participants’ food intake at lunch, not dinner. And the study only included 24 participants, so we should be wary of drawing solid conclusions from the findings.

A much larger 2007 study, which involved more than 25,000 adolescents, looked for links between skipping breakfast and having overweight. The researchers also assessed the roles of alcohol intake and levels of inactivity.

The scientists found that skipping breakfast had a stronger association with overweight than either alcohol consumption or levels of inactivity.

A 2020 systematic review and meta-analysis that appears in the journal Obesity Research & Clinical Practice concurs. After analyzing the results of 45 previous studies, the authors concluded:

“Skipping breakfast is associated with overweight/obesity, and skipping breakfast increases the risk of overweight/obesity.”

2. ‘Fat-burning’ foods can aid weight loss

Certain foods are referred to as “fat-burning.” This sounds too good to be true, and it probably is.
Some people claim that foods such pineapple, ginger, onions, avocados, asparagus, celery, chilies, broccoli, green tea, and garlic speed up the body’s metabolism, thereby helping the body burn fat.

There is little scientific evidence, however, that these foods can help reduce weight.

3. Weight loss supplements can help

Proponents of certain supplements claim that they, too, help the body burn fat. In reality, these are generally ineffective, dangerous, or both. The Food and Drug Administration (FDA) report that they have “found hundreds of products that are marketed as dietary supplements but actually contain hidden active ingredients contained in prescription drugs, unsafe ingredients in drugs that have been removed from the market, or compounds that have not been adequately studied in humans.”

Jason Humbert, a senior regulatory manager at the FDA, adds:

“We’ve also found weight loss products marketed as supplements that contain dangerous concoctions of hidden ingredients, including active ingredients contained in approved seizure medications, blood pressure medications, and antidepressants.”

4. Low fat foods aid weight loss

Of course, reduced fat or low fat foods are likely to contain less fat. However, these products sometimes compensate with added sugar or salt. Checking labeling is key.

Also, it is worth noting that “reduced fat” does not necessarily mean “low fat,” but simply that the fat content of a product is lower than the full-fat version.

5. Thou shalt not snack

People may believe that snacking is a cardinal sin of dieting. In some cases, though, snacking can help people manage their caloric intake more effectively. It is not so much snacking itself, but what one snacks upon that that counts.

Snacking may be more complex than it first appears. While some snack on celery and others on cookies, some people might snack because they are hungry and others because they are bored.

Having a piece of fruit or some low fat yogurt between meals, for instance, might reduce food cravings, keeping a person from overeating at mealtimes or resorting to more energy-dense snacks.

Some research has shown that people with obesity are more likely to snack than people without the condition. In this case, switching from unhealthful to healthful snacks may aid in weight loss, if this is a goal.

In general, snacking is multifaceted — it may support or hinder weight loss efforts, and in some cases it may have little effect. Older research, from 2007, investigated the role of snacking in weight loss. In the yearlong study, the researchers asked one group of participants to have three meals a day, without snacking. A second group was asked to have three meals and three snacks daily. Individuals in both groups consumed equivalent amounts of energy each day.

At the end of the study, the authors found no difference in weight loss between the two groups; snacking, it seems, neither helped nor hindered.

Another study, from 2011, investigated the “relationship between eating frequency and weight loss maintenance.” The researchers recruited participants who had previously had overweight or obesity but who had since maintained healthy weights.

They compared these individuals’ eating patterns with those of people with obesity and people with healthy weights who had never had overweight.

The team found that participants with healthy weights ate more snacks than those who had lost weight — and that people with overweight ate the fewest snacks.

Overall, the authors concluded that “Eating frequency, particularly in regard to a pattern of three meals and two snacks per day, may be important in weight loss maintenance.”

6. No treats allowed

This follows on from the myth above. Of course, limiting sugary, high fat treats is important, but cutting them out entirely is unnecessary and could be counterproductive.

As the British Heart Foundation explain:

“Depriving yourself of all the foods you enjoy won’t work. You’ll eventually give into temptation and abandon your efforts. There’s no harm in allowing yourself a treat now and again.”

7. Some sugars are worse than others

There is a rumor that minimally processed sugars, such as those in maple syrup or honey, are more healthful than white sugar. In reality, our bodies process sugar in the same way — regardless of its source. The gut reduces all sugars into monosaccharides.

Rather than looking at sugar processing, it is more important to note the amount of sugar in any food. All types of sugar provide around 4 calories per gram.

8. Cut out all sugar

Following on from the myth above, we know that all sugar is high in calories. However, a person looking to lose weight does not need to mercilessly cut sugar from their diet.

As with all things, moderation is key. It may instead be a good idea to avoid products with added sugar.

9. Artificial sweeteners are healthful

To lower their sugar intakes, many people opt for low- or no-calorie sweeteners, such as aspartame. This may reduce the number of calories consumed, but some studies have linked artificial, or nonnutritive, sweeteners to weight gain.

A systematic review and meta-analysis published in 2017 analyzed 37 existing studies involving a total of 406,910 participants to investigate the impact of sweeteners on cardiometabolic health.

According to the researchers, “Observational data suggest that routine intake of nonnutritive sweeteners may be associated with increased BMI [body mass index] and cardiometabolic risk.”

However, not all studies have reached this conclusion. Researchers and health experts continue to discuss the effects of nonnutritive sweeteners on weight loss and metabolic health.

10. You can target fat in specific areas

Some people are particularly keen to lose fat from certain areas, such as the thighs or abdomen. In reality, this targeting is not possible. All bodies respond differently to weight loss, and we cannot choose which bits of fat will go first.

However, if weight loss is paired with exercises to tone a particular area, it can give the impression of more region-specific weight loss.

11. This fad diet is excellent

Vast legions of diets have become fashionable only to fade into obscurity, making room for more. As the Centers for Disease Control and Prevention (CDC)

explain in a nutshell:

“[Fad] diets limit your nutritional intake, can be unhealthy, and tend to fail in the long run.”

The take-home

Overall, losing weight can be challenging. Our bodies evolved during leaner times, so they are primed to take on energy and store it. However, many of us live in a world where calories are readily available, and our bodies still store this energy as if it’s going out of fashion.

In general, reducing the caloric intake and exercising is the most reliable approach to weight loss. With that said, people with chronic diseases, including diabetes and obesity, should speak with their doctors before beginning a new weight loss regime.

It is also worth remembering that if anything seems too good to be true, it probably is — any “weight loss miracle” is unlikely to be miraculous. Most foods are not inherently unhealthful, but it is a good idea to consume high-sugar and high-fat foods sparingly.

For anyone embarking on a healthful weight loss program this year, good luck. 


About Cholesterol

Blood cholesterol is a waxy, fat-like substance made by your liver. Blood cholesterol is essential for good health. Your body needs it to perform important jobs, such as making hormones and digesting fatty foods. Your body makes all the blood cholesterol it needs, which is why experts recommend that people eat as little dietary cholesterol as possible while on a healthy eating plan.

Total cholesterol About 150 mg/dL
LDL (“bad”) cholesterol About 100 mg/dL
HDL (“good”) cholesterol At least 40 mg/dL in men and 50 mg/dL in women
Triglycerides Less than 150 mg/dL

What are signs and symptoms of high cholesterol?

High blood cholesterol doesn’t have symptoms, which is why getting your cholesterol levels checked is so important.

Knowing your cholesterol status can help you stay in control of your health.

What causes high cholesterol?

Certain health conditions, such as type 2 diabetes and obesity, can raise your risk for high cholesterol. Lifestyle factors, such eating a diet high in saturated and trans fats and not getting enough activity, can also raise your risk for high cholesterol. Some people who have a family history of high cholesterol can also be at risk for high cholesterol. All these factors are called “risk factors.”

You can’t control some of these risk factors, such as your age or your family history. But you can

What problems does high cholesterol cause?

Having high blood cholesterol can lead to a buildup called “plaque” on the walls of your arteries (a type of blood vessel).

As plaque builds up over time, the insides of your arteries narrow. This narrowing blocks blood flow to and from your heart and other organs. When blood flow to the heart is blocked, it can cause chest pain (also called angina) or a heart attack (also called myocardial infarction).

High cholesterol also increases your risk for heart disease and stroke, two leading causes of death in the United States.

How do I know if I have high cholesterol?

The only way to know whether you have high cholesterol is to get your cholesterol checked by your health care team. Talk with your health care team about how often you should have your cholesterol screened.

What can I do to prevent or manage high cholesterol?

Strong evidence shows that eating patterns that include less dietary cholesterol are associated with reduced risk of cardiovascular disease.

Your overall risk for high cholesterol depends on many factors.

Walking 8,000 steps just 1-2 days a week linked to significant health benefits

A study found hitting the 8,000-step goal just one to two days per week is still associated with a significant reduction in all-cause and cardiovascular mortality. Third Eye Images/Getty Images

  • Current research suggests that walking 8,000 brisk steps or more per day may be the sweet spot for receiving the health benefits walking provides.
  • People who have trouble finding time to walk each day of the week will be encouraged by a new study that demonstrates walking just one to two days is still associated with a significant reduction in all-cause and cardiovascular mortality.
  • The study’s authors found that each additional day walked confers greater benefits.

Briskly walking 8,000 or more steps each day of the week is associated with a significant decrease in all-cause and cardiovascular mortality. A new study finds, however, that people taking just 8,000 steps one or two days a week are also less likely to die over a 10-year follow-up period.

The study published in JAMA Network Open found that over a decade of follow-up, people 20 years or older who took 8,000 or more steps on one or two days a week were 14.9% less likely to die compared to people who were sedentary.

The risk of death dropped as the number of days involved increased. For example, exercising from three to seven days a week was associated with a 16.5% reduction in all-cause and cardiovascular deaths.

The same pattern held true for people meeting step goals of 6,000 to 10,000 steps.

Previous research found that mortality risk decreases up to 10,000 steps per day for people younger than 60 and 8,000 for people older than 60.

‘Weekend warrior’ style of exercising

The study’s findings pertain to both “weekend warriors,” people who confine their exercise to non-work days, and to people who steal a few hours to walk during the week.

The study cites recent data showing the average American takes just 4,800 steps a day, too few to provide much of a health benefit.

“Brisk walking” is defined as walking three miles an hour. If you can speak song lyrics but not sing them, you are walking briskly.

The current study compared data from the U.S. 2005 and 2006 National Health and Nutrition Examination Survey with the National Death Index up to the year 2019. It incorporated accelerometer data from 3,101 participants 20 years or older and was a nationally representative sample. It included a similar number of women and men, and 50.9% were White, 21.5% Black, 23.7% Hispanic, and 3.9% other race and ethnicity.

The participants most likely to walk 8,000 or more steps every day were more likely to be young, male, Hispanic, insured, and married. They were also typically never-smokers and were less likely to be obese or have comorbidities.

A daily challenge of walking 8,000 steps

For many people, walking 8,000 steps each day requires a significant commitment of time. 8,000 steps are about four miles, which, walking at three miles per hour, comes to a total of about an hour and 20 minutes every day. Steps can be taken simultaneously or in shorter periods of brisk walking.

The study was led by Dr. Kosuke Inoue of Kyoto University in Japan, collaborating with researchers from UCLA in California. Dr. Inoue explained why the study was undertaken:

“We started this study to answer the question one of my patients asked during an outpatient clinic: ‘It is hard for me to keep sufficient steps every day. Is it okay to focus on walking only during the weekend?’”

Steps studies often consider the value of a week’s worth of various step goals, and Dr. Inoue saw a lack of evidence regarding the possible benefits of walking just a few days a week.

“Given that a lack of time is one of the major barriers to exercise in modern society,” said Dr. Inoue, “our findings provide useful information to recommend walking even for a couple of days per week to reduce mortality risk.”

“This is one of the first studies to use direct measures of daily steps using a wearable accelerometer over a 10-year followup period,” said Dr. Paul Arciero, a professor in the Health and Human Physiological Sciences Department at Skidmore College, who was not involved in the study.

How walking benefits overall health

Walking is viewed as a simple, low impact means of making a person’s life less sedentary. A sedentary lifestyle has been linked to an increased risk of all-cause and cardiovascular mortality.

“Further, a sedentary lifestyle drastically increases the risk of cardiometabolic disease such as abdominal obesity, hypertension (high blood pressure), type 2 diabetes, stroke, heart disease, and certain inflammatory conditions and cancers,” said Dr. Arciero.

According to Harvard Medical School, taking one’s steps has additional, less-obvious benefits. Walking offsets the effect of weight-promoting genes, reduces breast cancer risk, and boosts one’s immune system. It can also lessen arthritis-based joint pain, and even a 15-minute walk can curb a craving for chocolate, both generally and in response to stress.

Dealing with limited time for walking

The study’s findings should provide valuable information for clinicians and health professionals, said Dr. Inoue. He suggested a reader’s takeaway should be that for people who have difficulties engaging in regular exercise, “achieving recommended daily steps only a couple of days per week can have meaningful health benefits.”

Describing the study’s conclusions as “encouraging,” Dr. Arciero suggested the study may help people who don’t have enough time to walk 8,000 steps a day overcome feelings that walking less is pointless.

“We now have scientific evidence that proves this mindset is not true, and even a couple of days is beneficial!” said Dr. Arciero.

He said the study underscores the value of increasing one’s daily step count:

“Always a good reminder that any amount of walking, even one to two days per week, is still better than no walking.”