Then it can remake them into any protein that we need. Once the proteins are broken down into amino acids in the digestive system, they are taken to our cells and kind of float around inside the cell, as those little individual beads in our analogy. And then inside the cell, your body basically connects them together to make the proteins that your body needs to make. We can make about half of the amino acids we need on our own, but we have to get the others from our food.
Scientists are not exactly sure, but most agree that there are around 20, different proteins in our body. Some studies suggest that there might be even more. They carry out a variety of functions from doing some metabolic conversions to holding your cells together to causing your muscles to work.
Their functions fall into a few broad categories. One is structural. Your body is made up of many different kinds of structures — think of stringlike structures, globules, anchors, etc. They form the stuff that holds your body together. Collagen is a protein that gives structure to your skin, bones and even teeth. Integrin is a protein that makes flexible linkages between your cells. Your hair and nails are made of a protein called keratin. In an analysis conducted at Harvard among more than , men and women who were followed for up to 32 years, the percentage of calories from total protein intake was not related to overall mortality or to specific causes of death.
Animal-based foods meat, poultry, fish, eggs, and dairy foods tend to be good sources of complete protein, while plant-based foods fruits, vegetables, grains, nuts, and seeds often lack one or more essential amino acid. Those who abstain from eating animal-based foods can eat a variety of protein-containing plant foods each day in order to get all the amino acids needed to make new protein, and also choose to incorporate complete plant proteins like quinoa and chia seeds.
The effects of protein deficiency and malnutrition range in severity from growth failure and loss of muscle mass to decreased immunity , weakening of the heart and respiratory system, and death.
In fact, many in the U. When we eat foods for protein, we also eat everything that comes alongside it: the different fats, fiber, sodium, and more. Research conducted at the Harvard Chan School of Public Health has found that eating even small amounts of red meat—especially processed red meat—on a regular basis is linked to an increased risk of heart disease and stroke , and the risk of dying from cardiovascular disease or any other cause.
One of the reasons why plant sources of protein are related to lower risk of cardiovascular disease compared to protein from red meat and dairy is because of the different types of fat in these protein packages. Plant-based protein sources are more unsaturated, which lowers LDL cholesterol—an established risk factor for heart disease.
Also, plant sources contain no cholesterol. Other factors are likely to contribute to the lower risk, but this is a key factor. Again, the source of protein matters more than protein quantity when it comes to diabetes risk. Eating more red meat predicts a higher risk of type 2 diabetes, while consuming nuts, legumes, and poultry is related to lower risk. When it comes to cancer, once again, the source of protein seems to matter more than quantity.
The same healthy protein foods that are good choices for disease prevention may also help with weight control. Though some studies show benefits of high-protein, low-carbohydrate diets in the short term such as the paleo diet , avoiding fruits and whole grains means missing out on healthful fiber, vitamins, minerals, and other phytonutrients.
Protein is a key part of any diet. The average person needs about 7 grams of protein every day for every 20 pounds of body weight.
Because protein is found in an abundance of foods, many people can easily meet this goal. Building off this general guidance, here are some additional details and tips for shaping your diet with the best protein choices:. Looking to reduce red and processed meats, but unsure where to start?
Here are a few approaches to cutting-back while keeping your meals satiating and flavorful. Ready to see how much you know about protein and healthy protein foods? Try this 10 question quiz to find out:. The contents of this website are for educational purposes and are not intended to offer personal medical advice. You should seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.
Never disregard professional medical advice or delay in seeking it because of something you have read on this website. The Nutrition Source does not recommend or endorse any products. Skip to content The Nutrition Source. Harvard T. The Nutrition Source Menu. Search for:. What Is Protein? For a pound person, that means about 70 grams of protein each day.
Table: Comparing protein packages. Heart disease Research conducted at the Harvard Chan School of Public Health has found that eating even small amounts of red meat—especially processed red meat—on a regular basis is linked to an increased risk of heart disease and stroke , and the risk of dying from cardiovascular disease or any other cause.
Cutting back on red meat could save lives: the researchers estimated that if all the men and women in the study had reduced their total red and processed red meat intake to less than half a serving a day, one in ten cardiovascular disease deaths would have been prevented.
In another study of 43, men that looked at both amount and sources of protein found that intake of total protein was minimally associated with heart disease risk, but intake of protein from red meat was associated with higher risk. The researchers compared people who ate diets with red meat with people who ate more of other types of foods i. Researchers found that when diets with red meat were compared with all other types of diets combined, there were no significant differences in total cholesterol, lipoproteins, or blood pressure, although diets higher in red meat did lead to higher triglyceride concentrations than the comparison diets.
Further evidence of the heart benefits of eating healthy protein in place of carbohydrate comes from a randomized trial known as the Optimal Macronutrient Intake Trial for Heart Health OmniHeart. A healthy diet that replaced some carbohydrate with healthy protein or healthy fat did a better job of lowering blood pressure and harmful low-density lipoprotein LDL cholesterol than a higher carbohydrate diet. Though weight loss was similar on the two diets, study participants on the high protein diet saw improvements in blood lipids and blood pressure.
Explaining the work, Brown said that given that "the cell is the functional unit of biology, it's just a natural curiosity to want to know what's in there and how much of each kind. Curiosity notwithstanding, there's another reason why scientists would want to tally up proteins. Many diseases are caused by either having too little or too much of a certain protein.
The more scientists know about how protein abundance is controlled, the better they'll be able to fix it when it goes awry.
Although researchers have studied protein abundance for years, the findings were reported in arbitrary units, sowing confusion in the field and making it hard to compare data between different labs. Many groups, for example, have estimated protein levels by sticking a fluorescent tag on protein molecules and inferring their abundance from how much the cells glow. But the inevitable differences in instrumentation meant that different labs recorded different levels of brightness emitted by the cells.
Other labs measured proteins levels using completely different approaches. To convert arbitrary measures into the number of molecules per cell, Ho turned to baker's yeast, an easy to study single-cell microbe that offers a window into how a basic cell works.
Yeasts are also the only organism for which there was enough data available to calculate molecule number for each of the 6, proteins encoded by the yeast genome thanks to 21 separate studies that measured abundance of all yeast proteins.
No such datasets exist for human cells where each cell type contains only a subset of proteins encoded by the 20, human genes. The wealth of existing yeast data meant that Ho could put it all together, benchmark it and convert the vague measures of protein abundance into "something that makes sense, in other words, molecules per cell," said Brown.
Ho's analysis reveals for the first time how many molecules of each protein there are in the cell, with a total number of molecules estimated to be around 42 million. The majority of proteins exist within a narrow range -- between and 10, molecules.
Some are outstandingly plentiful at more than half a million copies, while others exist in fewer than 10 molecules in a cell.
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