Eat to Your Heart’s Content — Part 4

It’s traditional for people to care for older family members rather than admission to care homes. The psychological benefits of living with your family in old age mean that people are happier and live longer. The Japanese may also have a genetic advantage. Two specific longevity genes are more common in Japan. DNA 5178 and the ND2-237 Leu/Met genotype both play a potential role in extending life by preventing the onset of some diseases. DNA 5178 helps people resist adult-onset type 2 diabetes, strokes and heart attacks. ND2-237 Leu/Met genotype provides resistance to strokes and heart attacks. Whereas there are lots of good lessons regarding not only diet but also lifestyle to be gleaned from our Japanese friends, genetic factors may also play a role.

The Okinawans have a saying: ‘Eat something from the land and something from the sea every day.’ Fish is packed with nutrients that many people lack, including high-quality protein, iodine and various vitamins and minerals. Fatty species are considered the healthiest because fatty fish, including salmon, trout, sardines, tuna and mackerel, are higher in fat-based nutrients. This includes vitamin D and omega-3 fatty acids.

Chapter 9: Eat to Your Heart’s Content

Omega-3 fatty acids are crucial for optimal body and brain function and strongly linked to a reduced risk of many diseases. To meet omega-3 requirements, eating fatty fish at least twice a week is recommended. If you are a vegan, opt for omega-3 supplements made from microalgae. Heart attacks and strokes are the two most common causes of premature death in the world and fish is considered one of the most heart-healthy foods you can eat. Unsurprisingly, many big studies show that people who eat fish regularly have a lower risk of heart attacks, strokes and death from heart disease. In one large UK study of 40,000 people, followed up over 18 years, fish eaters were 13 per cent and vegetarians 22 per cent less likely to have a heart attack than meat eaters. Fish also benefits the immune system and omega-3 fats in fish are especially important for the brain and the eye. Some fish are high in mercury, so fish low in mercury such as salmon, sardines, and trout are best. High levels of mercury have been linked to cardiovascular and brain disease, including possibly dementia, but the data are not definitive and levels are rarely high enough to cause concern in adults. In general, farmed and wild fish have similar mercury content but farmed salmon contains slightly more omega-3, much more omega-6 and more saturated fat. It also has 46 per cent more calories, mostly from fat. Conversely, wild salmon is higher in minerals, including potassium, zinc and iron and in vitamin D. As evidence that fish is good for the brain, people who eat fish regularly have more grey matter in the brain centres that control memory and emotion and better memory test results. Many of us have experienced depression at some stage in life, characterised by low mood, sadness, decreased energy and loss of interest in life. Although it isn’t discussed nearly as much as heart disease or obesity, depression is currently one of the world’s biggest health problems. Regular fish eaters are less likely to become depressed. Trials also reveal that, in patients who have been diagnosed with depression, omega-3 fatty acids and fish reduce symptoms and significantly increase the effectiveness of antidepressant medications, and even reduce suicidal thoughts and self-harm. In patients who had self-harmed, those random-ised to omega oil supplement for 12 weeks in addition to standard psychiatric care achieved substantial reductions in markers of suicidal behaviour and improvements in overall well-being compared to placebo and standard psychiatric care. Fish also benefits our sleep. In a study of middle-aged men, a meal with salmon three times per week over a six-month period led to improvements in both nocturnal sleep and energy by day. Red meat is a constant source of confusion for those looking to eat healthily – is red meat a good or bad food?

Chapter 9: Eat to Your Heart’s Content

Health benefits or otherwise of red meat consumption remain contentious. Blue Zone, Mediterranean and Japanese diets are all low in red meat, which is more common in affluent societies. One recent large-scale evaluation of combined evidence from a number of research studies examined the effects of red meat on a variety of health issues. The authors concluded that whereas there is some evidence that red meat consumption might be harmful, it is not strong enough to justify recommending that people change their dietary habits and desist from eating red meat. I have no doubt this debate will continue to rage because there are many vested interests and the outcomes are still unclear. Yet long-lived societies eat little or no red meat! Did you know that vitamin D is a hormone? It’s the only vitamin classed as a hormone, which explains its widespread influence on so many body functions. Vitamin D was discovered in 1920. You may well have seen old photographs of young children with grossly deformed legs due to rickets, caused by vitamin D deficiency in early childhood when bones are forming. Since discovery of the cause of rickets, foods for infants have been fortified with vitamin D and rickets has virtually disappeared from Western countries but deficiency still remains an issue in adulthood and older age and in some other susceptible groups such as the obese, the immunocompromised, people who cover up in the sun and people with bowel conditions such as inflammatory bowel disease or those with dark skin. These groups should take vitamin D supplements. In Ireland, 29 per cent of 18 to 30-year-olds and one in five people over 50 are vitamin D deficient in winter and spring. One in eight people over 50 are deficient all year round and half of people over 85 are deficient. The figures are the same in the UK and other countries at high latitude where foods are not fortified. There are three sources of vitamin D: sunlight, foods and supplements. It is very hard to get enough Vitamin D from food alone if we live at high altitudes, hence supplements are necessary. Foods high in vitamin D include fatty fish such as salmon, tuna and mackerel. Beef liver, cheese and egg yolks also provide small amounts. Vitamin D is best known for maintaining strong bones. It does so by helping the body absorb calcium from food in the gut. Calcium is one of bone’s main building blocks and is needed to prevent bone thinning (osteoporosis). Osteoporosis becomes much more common as we get older, particularly in women, although men can also be susceptible to it: one in seven people with osteoporosis is male. Good diet and exercise lower the risk of osteoporosis and bone scans should be conducted at least every five years after the age of 50 to check for osteoporosis because it can be treated.

Chapter 9: Eat to Your Heart’s Content

If it isn’t treated, bones start to fracture and it’s not uncommon for someone who’s experienced a fracture not to regain their previous level of function. It’s so frustrating when I encounter – which happens all too frequently – a patient with osteoporotic fractures which could have been prevented by earlier treatment. Vitamin D is important to the body in many other ways. Muscles need it for strength; nerves need it to carry messages from the brain and the immune system needs it to fight infections, including Covid-19. Our research supports a role for vitamin D in reducing the severity of Covid infections, including reducing deaths. Vitamin D may also be of benefit in age-related inflammation. The amount of vitamin D we need each day depends on age. For preventing the most serious effects of Covid-19, our research showed that intake of at least 800IU was associated with reduced severity in the response to infection, including much less frequent admission to intensive care. Daily doses of vitamin D up to 4000IU are safe. I personally take 1000IU per day and some of my colleagues take higher doses. Before discussing antioxidants, we should remind ourselves of what they do. Free radicals are the toxic molecules formed naturally in the cell during energy production. They cause ‘oxidative stress’, a process that triggers cell damage and plays a role in a variety of diseases. So antioxidants are good because they mop up free radicals and prevent them from causing toxic damage to the cell and consequent diseases such as heart attack, stroke, cancer, diabetes, macular degeneration and cataracts. Examples of antioxidants include vitamins C and E, selenium and carotenoids, such as beta-carotene, lycopene, lutein and zeaxanthin.